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Title: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 03:35:54 AM
Hi all,
First post.  I'll apologize in advance for my long posts but would sincerely and genuinely appreciate your help.  I am not sure if I am on the right forum to ask the questions I am going to but would like you not to get too pissed at me if I am on the wrong one and kindly ask that you try to help me or point me to the right forums. 

I have done a search here already for "power distros" and read many great posts regarding my questions and I think I have actually got most of them answered but just in case, I'll post my questions below.

Long story short, I own a smaller lighting, video, sound, and event production company and have questions regarding electrical situations for it.  I have coordinated shows in the past where we needed to get power installed on the outside of buildings to do some outdoor events that required us to have more power than your typical 20 amp wall outlet provides but I'll admit, I was simply in charge of coordinating the electrician to come and install what was needed and simply was told by the sound guy to have a specific type of 50 amp connector (I think it was a 50 amp female receptacle) installed to have his power distro plugged into it to provide power for his equipment.  Well, now I have purchased more equipment and I am slowly doing larger and larger shows and a few 20 amp outlets is not going to take care of my needs for what I am looking to do in the future.  So.......   

I believe my questions are basic because what I've seen in my head is common but maybe not.  Since I am now doing larger shows (but still "small" on many people's scale) on my own and want to be responsible for providing the sound and lighting equipment and running it and want to get into even larger events which will require more power, I am looking to have someone build a power distro for us OR.. purchase one to be used at various events when we do them in different locations.  We want to have a distro built that can be used as temporary power for us at the venues or places that just simply don't have enough power close enough to where we need to set up our amps, sound equipment, lighting and so on.

I know that in order to know how much power we would require, we would need to know what type of event it is and how much equipment it will take to put out the kind of sound we want AND the amount of lighting or video we want to showcase the event as well.  But let's just "assume" that when we add up all the amps/watts we need, we'll need up to 6,000-8,000 watts for sound and around 30-35 amps for lighting.  Keep in mind, we use a lot of LED lights and our newer moving head lights are also LED so the power requirements for lighting has now changed dramatically.  Anyway, so either 50 or possibly up to 100 amps will be needed for different events.   

What I would like to ask is what would "potentially" be needed for electrical needs in the way of power at "most" places?  I know this is a "loaded" question with all kinds of specifics needed (total calculations of equipment power needs based on total lights, amps, and other devices) but just to help you out, what I am pretty sure we need is a power distro that has an SOOW cable running from it to a 50 amp 14-50R style NEMA plug in receptacle.  I believe these provide either 50 amps on one 120 volt circuit or 2 separate 120 volt 50 amp circuits which would combine to provide 100 amps total.  That would be ideal for our power needs.

To keep it as simple as I can, I believe I found what we will need in the form of a plug in which is common at a lot of venues such as a conference center, event hall, arena, school, a gym, a bar or restaurant, and many other places.  It is a NEMA 14-50R style plug.  Here is a link to what I'm referring to:
http://www.myrv.us/electric/Pg/50amp_Service.htm

Now, one question I have is regarding how much power is available at these plugs in "most" typical setups?  Is it 240 volts with 2 separate 50 amp 120 volt circuits or only one 50 amp circuit on a 120 volt leg? 

In the link, it states that these plugs can provide either 120 or 240 volt service.  Since it has 2 hot leads available in this plug, from what I understand, you could have one 120 volt service on one side and another 120 volt service on another side which would total 240 volts to this plug.  If it is wired for 240 volt service, then we would need our male plug to be wired for 240 volt service and have a 4 conductor wire (with outside shielding of course) going from the male plug receptacle to our power distro box. 

So one question I have is:  when we are trying to figure out how to design our distro, do we design it with the idea in mind that we need a 100 amp box that will allow 240 volts to come in and split off into 2 separate 120 volt "legs" (I believe that's the correct term to use...please don't hate me if it's not) that would be 50 amps each?  Or, is it something else?  Even though the 100 amp box is rated for 100 amps, from what I am told, it is "actually" rated for 2 separate 120 volt 100 amp circuits (runs/legs/whatever) so it would actually be capable of 200 amps total but is called a 100 amp junction center.  So, in the case of using a 50 amp NEMA connector and SOOW cable for the extension run to the power distro, having a 100 amp box at our distro center would be more than sufficient correct? 

But here's the part where I'm confused.  If we have it wired up, would it make more sense to wire it for 240 volts and purchase 4/4 SOOW cable (our length of run might be 200 feet so I know that we would need 4/4 as a minimum but it might be 250 feet so I don't know if 4/4 is acceptable at 250 feet or if we have to jump to 2/4 SOOW cable) and have it wired for 240 service no matter what or only wire it for 120 volt service? 

I ask because I am "assuming" that these outlet/receptacles "typically" are wired for 240 volt service with each hot wire supplying 50 amps of service.  Like in the link, it would send 2 separate 120 volt 50 amp services through the plug in, through the 4/4 SOOW cable and to the junction box.  Which would then be split into two separate 50 amp 120 volt services (legs) and to the breakers for the 20 amp outlets on our board. And with this, it would have a total available output for our 20 amp outlets of 100 amps. 

If we have it wired to work for 240 volts, won't it still work in places that only have their 14-50R NEMA receptacles wired for 120 volts on one side as well?  In which case, even though it has the same receptacle, even though it's only wired for use of one 120 volt leg, we could still use that leg.  Or, do these plugs ALWAYS HAVE TO BE WIRED for 240 service? 

If we only wired it for 120 volt service, wouldn't we be limiting ourselves to only having that single 50 amp service at our junction box (instead of a full 100 amps) or am I missing something here?

As I stated earlier, "assuming" that we will AT LEAST have to have a 4/4 SOOW cable for a 250 foot run, I want to make sure that we aren't limiting ourselves if we're going to have this built with buying cable and so on.  And in that regard, I have also read that people have discussed the need to wire for 3-phase service which is typically 208 volts (if memory serves me correctly).  In which case, we would need to have a 5 conductor SOOW cable or something similar.  I know that this will add weight and cost to the cable but since the cable is already going to be damn expensive at 200 or 250 feet AND heavy anyway, even though it may add a few hundred dollars to the price, having the ability to also be able to tie into 3 phase service may be worth it right?

Now, currently, the equipment we use is simply amplifiers and lights that are wired for 110/120 volt service and as such, I am probably going to at least "try" to keep it that way for simplicity sake.  So, we may not even need to worry about 3 phase stuff until we could get bigger.  But, I would like to hear the options if you wouldn't mind (and have read this far). 

Also, I understand that the cost of a 200 amp box compared to a 100 amp box is virtually nothing so we will probably just put in a 200 amp box even though we will "probably" never need it.  I would just hate to run into the situation where we are doing a large enough event where we would have inflatables running (which takes a lot of power to run the fan motors and etc.) and maybe a larger show that needs more lighting and sound.  In which case, can we have two separate 50 amp SOOW cables going into this 200 amp junction box or is that something I'm way off on? 

And now that I think of it, if we do have inflatables rented from a different company, will their fans and equipment "typically" be 110/120 volt or will it be 3 phase since they are using fans?  Or does it depend on which type of fan they use?  If so, then I need to consider this obviously.

I have also heard of having an additional 14-50R plug or maybe only a 30 amp twist lock plug to allow you to run an additional power distro off of yours.  I suppose this could be done if we had another large amp rack that required a lot of power and we need to put them on the other side of the stage then this would be needed but for now, I think we'll try to keep them all close together.

So, for a 250 foot run, will we be ok with 4/4 SOOW cable or will we have to jump to 2/4 SOOW cable to meet code? 

And last, if we are running something that long, instead of purchasing the super expensive SOOW cable, why can't we simply use a 10-3 UF wire with ground cable (If we're only doing single phase)?  Like in these two links:

http://www.menards.com/main/electrical/rough-electrical/wire-cable/10-3-250-uf-with-ground-wire/p-1469728.htm

http://www.homedepot.com/Electrical-Wire/h_d1/N-5yc1vZbm7v/R-202316283/h_d2/ProductDisplay?catalogId=10053&langId=-1&storeId=10051#specifications

Since they are both rated for outdoor use and we would be using some of our distros outdoors, why couldn't we use these cables instead of purchasing something that is 4 to 6 times the cost?  Regardless of whether we would use these or SOOW cable or not, I realize that we may have to cover them to protect them from peope walking on them or having a vehicle drive over them.  I have often wondered why carnavals don't have to have all of those SOOW cables covered so maybe it isn't a requirement.  I don't know and if anyone knows, please fill me in.  But if it is, I would think it would be for an SOOW cable as well.  If it is, then I seen no reason why we couldn't use the cable from the links I posted above and save some money.   

I know these are questions about code and so forth but even though I haven't seen it done before, I am wondering why it wouldn't be acceptable since this cable is up to most codes or maybe even all of them. 

Also, as far as the amount of power we would need for our runs, let's just say we would need at a minimum of 50 amps but the 100 amps would be more desirable.  In which case, is the 14-50R receptacle that is good for 50 amps for 240 volts also good to break it down to 2 separate 50 amp legs at the junction box like I am thinking?

Any help would be much appreciated.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Tim McCulloch on January 29, 2013, 09:17:39 AM
Lonnie-

I don't have time to give you a point-by-point response (I've got a stage call in a few minutes), but I've posted a bunch of stuff about power distribution, some of which you may have already read.

You need to take a look at several parts of the National Electrical Code, especially Articles 520, 525, and 640.  These cover theatres (and other indoor performance venues), fairs & carnivals (outdoor performance includes concerts as well as carnivals, fairs, circuses, etc), and sound systems, respectively.  Also relevant are chunks of 200, 300, and the parts of 400 that cover flexible cords and cables that are listed in 520/525/640.

I'll answer your question about using UF.  You can't do it.  It is NOT listed for the use you plan for it.  That's pretty much the end of the discussion.  In some jurisdictions, you'll never see an inspector and you could get away with it... until you have a fire or someone is injured.  Then you'll find your insurance is void because you violated Code, and you'll leave yourself wide open to negligence lawsuits.  In other jurisdictions you WILL see an inspector, and he or she will red-tag your stage.  That means no show for you until the problems are corrected and the inspector satisfied with those corrections.  He might come back today... or tomorrow.  Explain that to your client.

I'm rigging today, so I won't have a chance to add to this until tonight... but until then, I'm sure some of the other forum users will have their comments about the other questions in your post.

Remember - the Code exists to keep from killing people and burning down buildings.  Second-guessing, making assumptions about equivalency, etc is a way of saying "I don't care if people die."
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 29, 2013, 09:27:07 AM
Hi all,
First post.  I'll apologize in advance for my long posts but would sincerely and genuinely appreciate your help.  I am not sure if I am on the right forum to ask the questions I am going to but would like you not to get too pissed at me if I am on the wrong one and kindly ask that you try to help me or point me to the right forums. 

I have done a search here already for "power distros" and read many great posts regarding my questions and I think I have actually got most of them answered but just in case, I'll post my questions below.

Long story short, I own a smaller lighting, video, sound, and event production company and have questions regarding electrical situations for it.  I have coordinated shows in the past where we needed to get power installed on the outside of buildings to do some outdoor events that required us to have more power than your typical 20 amp wall outlet provides but I'll admit, I was simply in charge of coordinating the electrician to come and install what was needed and simply was told by the sound guy to have a specific type of 50 amp connector (I think it was a 50 amp female receptacle) installed to have his power distro plugged into it to provide power for his equipment.  Well, now I have purchased more equipment and I am slowly doing larger and larger shows and a few 20 amp outlets is not going to take care of my needs for what I am looking to do in the future.  So.......   

I believe my questions are basic because what I've seen in my head is common but maybe not.  Since I am now doing larger shows (but still "small" on many people's scale) on my own and want to be responsible for providing the sound and lighting equipment and running it and want to get into even larger events which will require more power, I am looking to have someone build a power distro for us OR.. purchase one to be used at various events when we do them in different locations.  We want to have a distro built that can be used as temporary power for us at the venues or places that just simply don't have enough power close enough to where we need to set up our amps, sound equipment, lighting and so on.

I know that in order to know how much power we would require, we would need to know what type of event it is and how much equipment it will take to put out the kind of sound we want AND the amount of lighting or video we want to showcase the event as well.  But let's just "assume" that when we add up all the amps/watts we need, we'll need up to 6,000-8,000 watts for sound and around 30-35 amps for lighting.  Keep in mind, we use a lot of LED lights and our newer moving head lights are also LED so the power requirements for lighting has now changed dramatically.  Anyway, so either 50 or possibly up to 100 amps will be needed for different events.   

What I would like to ask is what would "potentially" be needed for electrical needs in the way of power at "most" places?  I know this is a "loaded" question with all kinds of specifics needed (total calculations of equipment power needs based on total lights, amps, and other devices) but just to help you out, what I am pretty sure we need is a power distro that has an SOOW cable running from it to a 50 amp 14-50R style NEMA plug in receptacle.  I believe these provide either 50 amps on one 120 volt circuit or 2 separate 120 volt 50 amp circuits which would combine to provide 100 amps total.  That would be ideal for our power needs.

To keep it as simple as I can, I believe I found what we will need in the form of a plug in which is common at a lot of venues such as a conference center, event hall, arena, school, a gym, a bar or restaurant, and many other places.  It is a NEMA 14-50R style plug.  Here is a link to what I'm referring to:
http://www.myrv.us/electric/Pg/50amp_Service.htm

Now, one question I have is regarding how much power is available at these plugs in "most" typical setups?  Is it 240 volts with 2 separate 50 amp 120 volt circuits or only one 50 amp circuit on a 120 volt leg? 

In the link, it states that these plugs can provide either 120 or 240 volt service.  Since it has 2 hot leads available in this plug, from what I understand, you could have one 120 volt service on one side and another 120 volt service on another side which would total 240 volts to this plug.  If it is wired for 240 volt service, then we would need our male plug to be wired for 240 volt service and have a 4 conductor wire (with outside shielding of course) going from the male plug receptacle to our power distro box. 

So one question I have is:  when we are trying to figure out how to design our distro, do we design it with the idea in mind that we need a 100 amp box that will allow 240 volts to come in and split off into 2 separate 120 volt "legs" (I believe that's the correct term to use...please don't hate me if it's not) that would be 50 amps each?  Or, is it something else?  Even though the 100 amp box is rated for 100 amps, from what I am told, it is "actually" rated for 2 separate 120 volt 100 amp circuits (runs/legs/whatever) so it would actually be capable of 200 amps total but is called a 100 amp junction center.  So, in the case of using a 50 amp NEMA connector and SOOW cable for the extension run to the power distro, having a 100 amp box at our distro center would be more than sufficient correct? 

But here's the part where I'm confused.  If we have it wired up, would it make more sense to wire it for 240 volts and purchase 4/4 SOOW cable (our length of run might be 200 feet so I know that we would need 4/4 as a minimum but it might be 250 feet so I don't know if 4/4 is acceptable at 250 feet or if we have to jump to 2/4 SOOW cable) and have it wired for 240 service no matter what or only wire it for 120 volt service? 

I ask because I am "assuming" that these outlet/receptacles "typically" are wired for 240 volt service with each hot wire supplying 50 amps of service.  Like in the link, it would send 2 separate 120 volt 50 amp services through the plug in, through the 4/4 SOOW cable and to the junction box.  Which would then be split into two separate 50 amp 120 volt services (legs) and to the breakers for the 20 amp outlets on our board. And with this, it would have a total available output for our 20 amp outlets of 100 amps. 

If we have it wired to work for 240 volts, won't it still work in places that only have their 14-50R NEMA receptacles wired for 120 volts on one side as well?  In which case, even though it has the same receptacle, even though it's only wired for use of one 120 volt leg, we could still use that leg.  Or, do these plugs ALWAYS HAVE TO BE WIRED for 240 service? 

If we only wired it for 120 volt service, wouldn't we be limiting ourselves to only having that single 50 amp service at our junction box (instead of a full 100 amps) or am I missing something here?

As I stated earlier, "assuming" that we will AT LEAST have to have a 4/4 SOOW cable for a 250 foot run, I want to make sure that we aren't limiting ourselves if we're going to have this built with buying cable and so on.  And in that regard, I have also read that people have discussed the need to wire for 3-phase service which is typically 208 volts (if memory serves me correctly).  In which case, we would need to have a 5 conductor SOOW cable or something similar.  I know that this will add weight and cost to the cable but since the cable is already going to be damn expensive at 200 or 250 feet AND heavy anyway, even though it may add a few hundred dollars to the price, having the ability to also be able to tie into 3 phase service may be worth it right?

Now, currently, the equipment we use is simply amplifiers and lights that are wired for 110/120 volt service and as such, I am probably going to at least "try" to keep it that way for simplicity sake.  So, we may not even need to worry about 3 phase stuff until we could get bigger.  But, I would like to hear the options if you wouldn't mind (and have read this far). 

Also, I understand that the cost of a 200 amp box compared to a 100 amp box is virtually nothing so we will probably just put in a 200 amp box even though we will "probably" never need it.  I would just hate to run into the situation where we are doing a large enough event where we would have inflatables running (which takes a lot of power to run the fan motors and etc.) and maybe a larger show that needs more lighting and sound.  In which case, can we have two separate 50 amp SOOW cables going into this 200 amp junction box or is that something I'm way off on? 

And now that I think of it, if we do have inflatables rented from a different company, will their fans and equipment "typically" be 110/120 volt or will it be 3 phase since they are using fans?  Or does it depend on which type of fan they use?  If so, then I need to consider this obviously.

I have also heard of having an additional 14-50R plug or maybe only a 30 amp twist lock plug to allow you to run an additional power distro off of yours.  I suppose this could be done if we had another large amp rack that required a lot of power and we need to put them on the other side of the stage then this would be needed but for now, I think we'll try to keep them all close together.

So, for a 250 foot run, will we be ok with 4/4 SOOW cable or will we have to jump to 2/4 SOOW cable to meet code? 

And last, if we are running something that long, instead of purchasing the super expensive SOOW cable, why can't we simply use a 10-3 UF wire with ground cable (If we're only doing single phase)?  Like in these two links:

http://www.menards.com/main/electrical/rough-electrical/wire-cable/10-3-250-uf-with-ground-wire/p-1469728.htm

http://www.homedepot.com/Electrical-Wire/h_d1/N-5yc1vZbm7v/R-202316283/h_d2/ProductDisplay?catalogId=10053&langId=-1&storeId=10051#specifications

Since they are both rated for outdoor use and we would be using some of our distros outdoors, why couldn't we use these cables instead of purchasing something that is 4 to 6 times the cost?  Regardless of whether we would use these or SOOW cable or not, I realize that we may have to cover them to protect them from peope walking on them or having a vehicle drive over them.  I have often wondered why carnavals don't have to have all of those SOOW cables covered so maybe it isn't a requirement.  I don't know and if anyone knows, please fill me in.  But if it is, I would think it would be for an SOOW cable as well.  If it is, then I seen no reason why we couldn't use the cable from the links I posted above and save some money.   

I know these are questions about code and so forth but even though I haven't seen it done before, I am wondering why it wouldn't be acceptable since this cable is up to most codes or maybe even all of them. 

Also, as far as the amount of power we would need for our runs, let's just say we would need at a minimum of 50 amps but the 100 amps would be more desirable.  In which case, is the 14-50R receptacle that is good for 50 amps for 240 volts also good to break it down to 2 separate 50 amp legs at the junction box like I am thinking?

Any help would be much appreciated.
You win the award for most self-disclaimed post in a while.  Thanks for doing some research before a "tell me what to do" question.

Condensing some things, here are some principles/answers for several of your questions:

1. DO NOT build a distro yourself.  In addition to all of the pitfalls of potentially doing it wrong and being liable for injury and/or property damage, it's not even economically feasable compared to something like this: http://www.peavey.com/products/index.cfm/item/964/117526/distro

2. Re 240v/120v and current: A 50A 240v circuit breaker is - get this - 50A.  If your load is connected across both hot wires (240 volts), you have up to 50A before you blow the breaker.  If your load is connected from a hot wire to a neutral wire (120 volts on one leg of the circuit), you also have up to 50A before you blow the breaker.  You do have another leg available - the other hot wire to neutral - that you can also potentially draw up to 50A on for potentially 100A total at 120 volts, but it's still technically a 50A system, since any single load exceeding 50A will trip the breaker.

3. Re load and wire sizes: Overcurrent protection is designed to protect the supply wiring.  For every step down in distribution, you need overcurrent protection sized appropriately for the wiring.  For example, if the building has a 400A service from the power utility, it will have a 400A breaker system designed to protect the supply wiring.  If that service is broken down to 6 100A sub panels arranged througout the building, each panel will have a 100A breaker to protect the supply wiring from the main panel to the sub panel.  From there, each branch circuit will have a 15A, 20A, 30A, etc. breaker sized to the next stage of the load.

In the distro situation:  You need to protect your feeder wire somehow.  If you have a 100A panel fed by a piece of 10/4 wire that could potentially be plugged into a supply of greater than the 30A rating of the 10/4 wire, you must have a master breaker that will ensure that you won't draw more than the rated 30A over this wire.  Alternatively, it may be acceptable to put a plug on your wire - NEMA 14-30 for example, such that as long as this plug is always plugged into legally wired 14-30R receptacles, you may not need a master breaker on your distro, as the breaker protecting the 14-30R you're plugging into is already protected in the panel.

4: Re 120v or 240v on a 14-50R: Any time you see a Nema 14-50R receptacle, it better have all 4 wires connected appropriately - in other words you will always have two hot wires to opposite phases allowing 240v/208v loads, a neutral wire, and a ground wire.  If this is not the scenario you're seeing DO NOT USE IT!!! IT IS UNSAFE!!!

5: Reading farther down your post it seems a lot of your confusion is related to how to use a NEMA 14-50R.  Distros such as the Peavey I linked to have half the circuits wired to one leg, and half to the other leg, providing entirely 120v power to the user, in this case two circuits of 50A at 120 volts, broken out to 6 20A circuits at 120v.  Don't worry that in other situations you can use the 14-50R to provide 240volts as well; that's another problem.  There's very little gear at the level you're at that can run at 240v.

6: Re wire length and ampacity: 250' is too long for your distro.  Cable length causes voltage drop, which requires increasing the size of your supply wiring in order to have the appropriate power left at the end.  I would suggest putting at most a 75' piece of 4/4 SOOW on the Peavey distro, so that you're not always carrying 400lbs of copper around.  If you need more length than this, you can make a NEMA 14-50 "extension cord" with a plug on one end and a receptacle on the other end.  Depending on your total length, you may indeed need to go up a cable size.

7: Re cable type: A NEMA 14-series plug/receptacle requires 4 wires, so anthing /3 is not correct.  SOOW cable is rated for portable use in our industry because being fine stranded wire it can withstand coiling and uncoiling, and because the thick jacket can stand up to being dragged on the ground.  UF cable is inappropriate for portable use because it's solid wire and therefore will break quickly if coiled and uncoiled more than a few times, and because the jacket is different.  It's also impossible to work with in a portable application.  Go look at a piece and you will see.

8: Re what you will "need": A NEMA 14-50 service provides a lot of power and will surely cover the loads you have described.  It's a great step up from a bunch of orange extension cords plugged into every outlet you can find, and pretty much the largest thing average users can use without requiring an electrician.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Jerome Malsack on January 29, 2013, 09:43:00 AM
I have an electrical supply outlet near my home that the electricians source their materials.  I would hook up with an electrician and get some advice on setting it up.  Also you would be better served by getting the 10/4 cable because the outlet you want to work with.  If you plan to be over 50 feet I would look into 8/4 cable. 

Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 29, 2013, 09:47:42 AM
I have an electrical supply outlet near my home that the electricians source their materials.  I would hook up with an electrician and get some advice on setting it up.  Also you would be better served by getting the 10/4 cable because the outlet you want to work with.  If you plan to be over 50 feet I would look into 8/4 cable.
The only outlet he's mentioned is a NEMA 14-50.  Neither 10/4, 8/4, or even 6/4 are appropriate for that.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: roblavender on January 29, 2013, 01:43:11 PM
One thing to know about any distro is what 120 outlet circuit is on which supply leg.

On the Peavey Distro: (from the owners manual) "When plugging in equipment, divide the load as follows: The X leg supplies circuits A,C & E while the Y leg powers circuits B, D, & F. Each leg can provide 40 amps so divide your loads so they are balanced between the legs (for example, put one subwoofer amp on each leg, not both on the same leg)."

I hate to do it, but I have to disagree with Peavey on this one. If you don't want to fight buzz and hum induced by the lighting system, then place the sound system on one leg and lighting system on the other leg.  Yes it is always a good idea to balance the two legs as much as possible, but you will never get the actual (systems in use) load to balance in portable distro use anymore than you can maintain such a balance in your electrical use at home. Though all electricians are taught to balance the load as much as is possible, and so should sound & lighting contractors. Just not to the detriment of the show.

The alternative is to have separate distro systems. one for sound and one for lighting. The problem there is that it is rare to find venues of the type and size mentioned by Lonnie that have more than one 240 outlet available. But having separate distros for each system is the way to go IMHO.

BTW: We have had several distro systems built for us by qualified electricians who are familiar with the entertainment industry. It can certainly be done. However it doesn't save you much money and they tend to be much larger than the rack mount one such as the Peavey.

I have had good results with the Furman rack mount power distros too. The run in the $550 to $600 range depending on where you buy them.  http://www.furmansound.com/product.php?id=ACD-100
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: g'bye, Dick Rees on January 29, 2013, 02:25:00 PM

BTW: We have had several distro systems built for us by qualified electricians who are familiar with the entertainment industry. It can certainly be done. However it doesn't save you much money and they tend to be much larger than the rack mount one such as the Peavey.

And as such they may invalidate your liability insurance.  While it may be OK for you to assume the risk, it is not kosher to state to others that "it certainly can be done".

Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Tim McCulloch on January 29, 2013, 02:29:11 PM
One thing to know about any distro is what 120 outlet circuit is on which supply leg.

On the Peavey Distro: (from the owners manual) "When plugging in equipment, divide the load as follows: The X leg supplies circuits A,C & E while the Y leg powers circuits B, D, & F. Each leg can provide 40 amps so divide your loads so they are balanced between the legs (for example, put one subwoofer amp on each leg, not both on the same leg)."

I hate to do it, but I have to disagree with Peavey on this one. If you don't want to fight buzz and hum induced by the lighting system, then place the sound system on one leg and lighting system on the other leg.  Yes it is always a good idea to balance the two legs as much as possible, but you will never get the actual (systems in use) load to balance in portable distro use anymore than you can maintain such a balance in your electrical use at home. Though all electricians are taught to balance the load as much as is possible, and so should sound & lighting contractors. Just not to the detriment of the show.

The alternative is to have separate distro systems. one for sound and one for lighting. The problem there is that it is rare to find venues of the type and size mentioned by Lonnie that have more than one 240 outlet available. But having separate distros for each system is the way to go IMHO.

BTW: We have had several distro systems built for us by qualified electricians who are familiar with the entertainment industry. It can certainly be done. However it doesn't save you much money and they tend to be much larger than the rack mount one such as the Peavey.

I have had good results with the Furman rack mount power distros too. The run in the $550 to $600 range depending on where you buy them.  http://www.furmansound.com/product.php?id=ACD-100

The text in bold is bullshit from a electrical engineering standpoint.  All the hot phase legs share a neutral and ground, and THAT is where you get your harmonic contamination.  Putting all of one type of load will likely insure that you have a very unbalanced loading situation that may exacerbate the neutral issue, not make it better.

We share power with lights all the time.  The relative noise levels are dependent on how well the dimmers are filtered and how many audio devices have the "pin 1 problem".  With ETC, Strand or Leprecon dimmers, we have zero noise.

At our new arena, each side of the upstage area has multiple service disconnects, but there is only one transformer serving each side.  To this day, I get road show guys that see separate switches and assume each has its own transformer... they don't, but for some reason the PA is quiet even though it shares the same 3 phase legs, neutral and ground with lighting, video, and automation.

As for building distros, in theory any competent industrial electrician can do it.  The reality is that either our insurance, or the client's insurance or the venue may require only *U.L. listed* distros, and that means the whole assembly, not just the components must be UL listed.  When it comes to purchasing distros, one will find most budget distros do not bear the UL sticker.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 03:24:25 PM
The text in bold is bullshit from a electrical engineering standpoint.  All the hot phase legs share a neutral and ground, and THAT is where you get your harmonic contamination.  Putting all of one type of load will likely insure that you have a very unbalanced loading situation that may exacerbate the neutral issue, not make it better.

+1 on that. Like so many myths in this industry, I'd really like to know where that one came from. If you want real isolation between lights and sound, you need separate services derived from separate transformers. Splitting them up on different phases does no such thing.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 06:57:26 PM
You win the award for most self-disclaimed post in a while.  Thanks for doing some research before a "tell me what to do" question. Well, I'm not claiming to know "much" about what I'm asking and am definately NO electrician by any means so that's why I'm asking the questions.  I want to do it right.

Condensing some things, here are some principles/answers for several of your questions:

1. DO NOT build a distro yourself.  I wasn't planning on it and would either have a qualified electrician build it or purchase one.  In addition to all of the pitfalls of potentially doing it wrong and being liable for injury and/or property damage, it's not even economically feasable compared to something like this: http://www.peavey.com/products/index.cfm/item/964/117526/distro (http://www.peavey.com/products/index.cfm/item/964/117526/distro)I've seen this distro and although it is nice, I would probably skip this one and jump to the 100 amp distro that Furman now has since the price is pretty much the same at around $550.  Furman also has a 120 amp distro for around $675 now.  They actually look pretty decent but everyone's use will be different.  But the thing is, if I am never in a place that can supply 100 or 120 amps to my distros, then it "almost" makes no sense to get something that big.  I believe in having more than enough because like with volume, you can always use less but you can't (turn it up) and use more.  At least with regards to power in this case.  So, I would like to have an 80, 100, or 120 amp distro but if I'm never going to get that kind of poower to begin with, then it's virtually pointless and I would rather keep it to what I will be using in "most" cases.  If I have to do something different in 5% or 10% of my shows, then I figure something else out like renting a generator or doing something different as needed.

2. Re 240v/120v and current: A 50A 240v circuit breaker is - get this - 50A.  Are you sure about that?  Don't get the wrong idea by my questioning your response because I've read a lot of what you've said about other distro questions on here (yes, I did see many familiar names around this forum) and I've "sponged" some of the things you've said as well Tim but I just don't understand this.  From what I have been reading, it is 2 separate 120 volt services (legs) in that 50 amp 14-50R plug when connected with 240.  That is, "if" they wired it up to be 240 and NOT JUST 120.  As it stated in the link I provided, it could be one or the other.  In which case, if it was wired for just one 120 volt service, that would provide 50 amps and not 25 amps wouldn't it?  So, if you have two 120 volt "legs", wouldn't that be 50 amps per leg?  Two "hots", one neutral, and one ground.  And each one providing 50 amps of service.  So, wouldn't 50 + 50 = 100 amps at the junction box (distro area)?  One 120 volt service for one side of the junction and one 50 amp service for the other side.  Or am I completely off base?  This is probably where the understanding of how it is all distributed gets me confused so please don't take my comments as trying to be an ass but simply trying to get the correct info.    If your load is connected across both hot wires (240 volts), you have up to 50A before you blow the breaker.  If your load is connected from a hot wire to a neutral wire (120 volts on one leg of the circuit), you also have up to 50A before you blow the breaker.  You do have another leg available - the other hot wire to neutral - that you can also potentially draw up to 50A on for potentially 100A total at 120 volts, but it's still technically a 50A system, since any single load exceeding 50A will trip the breaker.  Ok, so let's just "assume" that we want to ensure that we have as much power available to run our amps and light throughout the night.  And although amps will flucuate with power draw from the music throughout the evening, let's just assume that we're pumping out some heavy music with large bass beats/tones/kick drum/whatever you prefer to call it, and we've got our lights going too, if we're trying to get a good 5,000 to 6,000 watts out of our system on a pretty regular basis and we've got a live band drummer doing some multiple hits on his kick drum or a bass player flickin' their fingers nonstop at the same time AND...we're doing some lights at the same time as well, I would assume that we would easily be pulling 60 or 70 amps at a given time.  Potentially 80 or more if we're cranking.  Or let's just say it was music.  Whichever you want to choose.  Are you saying that no matter what, we can't go over the 50 amp limit on both legs combined with a total of 50 amps at once because we'll run the risk of popping the 50 amp breaker back at our plug in point (at the venue, bar, building, outdoor pole, whatever)?

3. Re load and wire sizes: Overcurrent protection is designed to protect the supply wiring.  For every step down in distribution, you need overcurrent protection sized appropriately for the wiring.  For example, if the building has a 400A service from the power utility, it will have a 400A breaker system designed to protect the supply wiring.  If that service is broken down to 6 100A sub panels arranged througout the building, each panel will have a 100A breaker to protect the supply wiring from the main panel to the sub panel.  From there, each branch circuit will have a 15A, 20A, 30A, etc. breaker sized to the next stage of the load.  I figured that and it just makes sense.  If we're breaking up the 400 amp power, I could understand how NONE of the distributed power centers should be able to have an 800 amp service on it.  If I may ask though, why is it allowed to have more amp distribution centers than only 4 separate 100 amp services?  Since 4 x 100 = 400, shouldn't it be limited to only 4 separate 100 amp services?  6 x 100 = 600 and if it is "possible" to have all 6 separate 100 amp services pulling some heavy loads all at once, it could obviously trip the breaker at the 400 amp part.  Again, I understand that loads fluctuate and the chances of all 6 separate 100 amp services using all of their load capacities at once are slim however, why even let that be possible?  Why not limit it to only 4 separate 100 amp services?  Or does having 6 or maybe even 8 separate 100 amp services not put too much of a stress on the total 400 amp load available to all of them?  Since they are not all using 100 amps at once, is it not a big deal for electrical companies to set them up this way?  Obviously they know so I'm just curious.

In the distro situation:  You need to protect your feeder wire somehow.  If you have a 100A panel fed by a piece of 10/4 wire that could potentially be plugged into a supply of greater than the 30A rating of the 10/4 wire, you must have a master breaker that will ensure that you won't draw more than the rated 30A over this wire.  Alternatively, it may be acceptable to put a plug on your wire - NEMA 14-30 for example, such that as long as this plug is always plugged into legally wired 14-30R receptacles, you may not need a master breaker on your distro, as the breaker protecting the 14-30R you're plugging into is already protected in the panel.  I understand this too but I am not planning on only using a 30 amp service.  And what you're referring to is probably very similar to the size of the nozzles of unleaded and diesel at a fuel/gas station.  Diesel nozzles are larger in diameter than unleaded fuel nozzles for your fuel fill tank.  That way, you can't "accidentally" fill your car with diesel.  Unfortunately for Diesel truck owners, they "can" fill their pickups with unleaded and as an auto technician (mechanic) of 7 years, I know that's happened a few times before.  So, in electricity, as long as people are doing things correctly (oh the thought)...then you really "can't" plug in something to the wrong outlet and draw more power than is allowed OR SHOULD BE allowed since the plug/receptacle (like our nozzles) doesn't fit.  I understand this and it's a great thing that electricity is set up this way.   However, people "can" modify a plug in or NOT use the correct gauge wire for some plugs as needed.  But, I am planning on using either 4/4 or maybe even having to jump to 2/4 (or 4/5 or 2/5 if we're considering 3 phase) since we're looking at 250 feet.

4: Re 120v or 240v on a 14-50R: Any time you see a Nema 14-50R receptacle, it better have all 4 wires connected appropriately - in other words you will always have two hot wires to opposite phases allowing 240v/208v loads, a neutral wire, and a ground wire.  Okay, so this is sort of a repeat question regarding the link  I provided originally then.....in that link, it states that a 14-50R plug can be wired for just 120 and NOT NECESSARILY 240 service.  In which case, how are they accomplishing this?  Wouldn't that mean that they (the venue that had the 14-50R plug installed) hooked it up using only one side of the connetor to use 120 volt service?  Meaning the other side wasn't hooked up at all?  Even thought you say "it better", even though it "should" have it hooked up, isn't it acceptable not to?  Again, as I mentioned, to me, it doesn't make sense to NOT use that plug to its full potential if you're going to have it installed but then why did they design them to be used for either application?  I wish that if this were the case, it was just simply mandatory that all of these plugs ACTUALLY HAD to be wired for 240 service.   Or, are you saying that they actually ARE SUPPOSED to be wired to have 240 service?  And as a precaution, it's obviously not hard to learn how to pack a multimeter and turn the knob to the little "V" with a squiggly line and put one lead on one side and the other lead on the other side and check them to ground and neutral as well.  To me, it only seems to make sense if you're going to be running that much power anyway right?  If this is not the scenario you're seeing DO NOT USE IT!!! IT IS UNSAFE!!!  Again, I'll refer back to my question about it's "dual" usage ability.  But thanks for the warning and I've got it locked in my head.

5: Reading farther down your post it seems a lot of your confusion is related to how to use a NEMA 14-50R.  Distros such as the Peavey I linked to have half the circuits wired to one leg, and half to the other leg, providing entirely 120v power to the user, in this case two circuits of 50A at 120 volts, broken out to 6 20A circuits at 120v.  I believe Peavey's distro is rated at 80 amps according to their info and if this is the case, how are they getting away with this?  If it is rated at 80 amps, then I want to be able to use all 80 amps if needed.  I don't want to use "part" of it and have to figure out what "part" of it I can use at what time.  And besides, to me, that is sort of counterproductive and unsafe and sort of goes against the whole "nozzle" (plug in) theory of making things the way they should be built to prevent a problem or an unsafe situation.  Actually, if you look at the specs on the distro (which I just did) it says 80 amps "total load" and it shows 40 amps from a 240 circuit or as stated here:  Input 240v/40A (ETL) according to their website. Don't worry that in other situations you can use the 14-50R to provide 240volts as well; that's another problem.  There's very little gear at the level you're at that can run at 240v.  Yeah, I'm not really worried at this point about 240 stuff.  Although I can get it, I would rather keep it as simple as possible and also be as consistent as possible.  I would hate to have something be wired for 240 or a few things wired that way and then happen to be at a place where something happens to their 240 service and then we can't use a standard 120 outlet if we "had" to.  Sure, more than likely that will "never" happen but I would rather NOT be wrong.  Probably not much that I would be dealing with though that I would "need" to be able to use a standard 120 outlet in that situation anyway.  If something "that" drastic happens, a 120 outlet probably isn't saving a show of that size.

6: Re wire length and ampacity: 250' is too long for your distro.  No, it's not and you know that there are longer ones out there.  I've seen 200 to 250 foot runs.  And we've all seen longer ones so to say that it is "too long" is probably not correct. Cable length causes voltage drop, which requires increasing the size of your supply wiring in order to have the appropriate power left at the end.  I understand this which is why I have been trying to ask a lot of questions and do research about what cable will be needed for a 250 foot run.  I would suggest putting at most a 75' piece of 4/4 SOOW on the Peavey distro, so that you're not always carrying 400lbs of copper around.  Weight is not the issue here.  Flexibility is.  Preparedness is.  Let's think of it like this:  First, let's say you're at a high school gym and the area you want to set up at is quite a ways away from where the 14-50R power source is.  Now think about "most" situations like this where the power source isn't on the inside of the stage or under it or close to the basketball court in the gym.  The power source is "usually" down and around the stage or behind a door in a room/closet/electrical room that is another 20 to 30 feet around the corners by the time you get there.  And then, from there, to get to your stage area where you NEED to set up your amps and other high powered equipment (the equipment that needs this power distro), it is ANOTHER 60 or 80 feet across the gym floor.  BUT...BUT...BUT...that is a "straight shot" from the electrical power supply to the stage area.  So, we're talking about 85 to 110 feet give or take.  Well, to me, I don't think running a cable across the floor where people may be walking or sitting or dancing and so on is a good idea.  Sure, it may be "acceptable" but I would rather run the cable around the corners and out of the way so we can "minimize" an issue.  We would need to put covers over the cable in doorway areas and exits and that's about it.  The rest, we can run along walls and so on.  In this case, 75' or even 100' or 125' is NOT going to cover it.  So, we will NEED something longer.  Furthermore, I''m thinking about other events such as outdoor events where the power source may be a long distance away.  ----And actually, that is why this question has come up for me BECAUSE I've got an event I'm considering putting together for this summer and we're trying to figure out where to get power.  The area we are looking at is owned by a lady that owns the buildings right beside it that just had some brand new power put in on the side of one of her buildings last year for a famer's market outdoor type of event.  However, they put in 4 - quad 20amp GCFI outlets and no 14-50R receptacle like I am thinking.  Which isn't no big deal because I'm sure they could add one if they wanted.  HOWEVER...the BIG KICKER is:  this power source is 235' 240' away from the stage area where I would need to set up my equipment.  So......if we're going to have to run something, then we're looking at about 250'.  I'm thinking for future shows too.  We're talking to the electrical company about putting in a metered plug close to the stage area but unfortunately, they may not be able to since this area is on the wrong side of the road.  They may have to dig or figure out a way to put in a pole tall enough to get metered power to the area I want.  We already got an estimate for temporary power but it was about $1350 and only lasts for 3 months.  So, to me, that isn't economical so I'm looking for other options.  If you need more length than this, you can make a NEMA 14-50 "extension cord" with a plug on one end and a receptacle on the other end.  To me, I can figure that if I'm in a smaller place doing smaller shows, I can figure out how to utilize 3 or 4 of their standard wall outlets and run cords as needed.  But if I'm doing anything over 2 separate outlets, there's a HUGE chance that I'm just assuming that I'm going to be plugging into their 14-50R plug with my distro for simplicity sake.  And, in these cases, having the extra cable length needed and the weight of it isn't going to bother me.  I could easily build a rack to accomodate the cable and I could simply roll it in the case as needed and unroll whatever I needed for each show.  If I only needed 50' or 75' for a show, then I only take out that much and the rest sits nicely rolled into the rack.  But when I need 150' or 200', well....then it can be used too.  An additional cord just means more money for plugs and/or receptacles and why spend more money?  If I'm going into this with the idea that I'm going to have to spend $1000 - $1300 or so on cable in the first place, then it doesn't make sense to me to limit myself to only 75' when the one show I may need to start out using it for is going to require at least 235' or 240'.     Depending on your total length, you may indeed need to go up a cable size.  Yes, if I can do 4/4 (or 4/5) at 250' and it is acceptable to do so, then I will go with that.  If I have to do 2/4 (or 2/5) then I'll do that if needed.  I hope I can get by with 4/4 because the cost will be significantly higher with 2/4 but that's life if I have to jump to 2 gauge.

7: Re cable type: A NEMA 14-series plug/receptacle requires 4 wires, so anthing /3 is not correct. So you're saying that they "can't" hook up a 14-50R receptacle to use ONLY 3 wires?  Or are you saying they "shouldn't?"  I am more concerned with what code is.  I understand that "technically" because there are 4 lugs in the receptacle they can hook up, they "could" only use 3 of them but are they "required" by code to hook up all 4 or can they do only 3?  (Again, I'm referring back to my questions about 120 volt service in these plugs vs. 240 volt service) SOOW cable is rated for portable use in our industry because being fine stranded wire it can withstand coiling and uncoiling,Makes sense compared to the harder (yet still soft) copper wire in the UF cable I mentioned. and because the thick jacket can stand up to being dragged on the ground.  UF cable is inappropriate for portable use because it's solid wire and therefore will break quickly if coiled and uncoiled more than a few times, and because the jacket is different.Well, the jacket is different on a UF cable but it still appears to be thicker than an SOOW cable jacket.  But not as "flexible" I suppose.  It's also impossible to work with in a portable application.Well, that's up for debate.  "Impossible" to you may simply mean a pain in the ass.  If a person wanted to take the time to roll and unroll this cable, I don't see how it would be impossible.  Besides, the overall size of 250' of cable compared to a 4/4 SOOW cable is signifcantly smaller in a UF cable.  It's about 1/6 of the size.  Maybe even smaller.  Plus, it does come rolled on a wooden spool so it "can" be rolled since it comes that way.  However, I would understand how over time it may end up hurting the cable if you constantly roll and unroll it.  It may hurt the copper inside of the cable.  That I didn't think of till you mentioned it.  Go look at a piece and you will see.  I've seen them many times but I'll be going tonight to check some things out and do some more research.

8: Re what you will "need": A NEMA 14-50 service provides a lot of power and will surely cover the loads you have described.  It's a great step up from a bunch of orange extension cords plugged into every outlet you can find, and pretty much the largest thing average users can use without requiring an electrician.
Yep, that's why I wanted to step up to something like this.  But, I want to make sure my investment will cover what I want to use it for.  If I buy a Peavey distro that says it's capable of 80 amps or a Furman distro that is either 100 or 120 amps, I want to make sure I can utilize them to their fullest potential.  Otherwise, I could EASILY spend $2000 or more on cable and distros to only end up with something that "still" won't be usable.  Or worse yet, not up to code.


Thanks for the reply Tom.  I appreciate the info so far.   :)
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 07:14:59 PM
The alternative is to have separate distro systems. one for sound and one for lighting. The problem there is that it is rare to find venues of the type and size mentioned by Lonnie that have more than one 240 outlet available. But having separate distros for each system is the way to go IMHO.
BTW: We have had several distro systems built for us by qualified electricians who are familiar with the entertainment industry. It can certainly be done. However it doesn't save you much money and they tend to be much larger than the rack mount one such as the Peavey.
I have had good results with the Furman rack mount power distros too. The run in the $550 to $600 range depending on where you buy them.  http://www.furmansound.com/product.php?id=ACD-100 (http://www.furmansound.com/product.php?id=ACD-100)

Rob, I agree that having two separate distros would be "ideal" but the reality of the situation is:  "most" places aren't going to have more than 1 single 14-50R receptacle to plug into.  Well, at least not smaller places like bars or small gyms and so on.  In the places that do have more than one receptacle, then we could consider renting one that could take care of our needs for the evening. 
 
 
Keep in mind, even though you may not know, I'm not just going to go into these places without asking at least a few questions first.  As I read on some other posts about distros, one gentleman no longer uses a distro because it got too confusing when he was trying to get "accurate" information from the bar owners or venues.  When he would ask if they had a 50 amp outlet, they may have said yes when really they didn't know and actually didn't have one.  Or, what they did have wasn't hooked up properly (like Tom mentioned) to begin with.  So, the 50 amp plug was renderred useless anyway.  So, he decided to take a different approach and use regular 20 amp wall outlets on separate breakers.  As a result, he's said he's had great success with running shows on 3, 4 or maybe 5 outlets.  For him, that's great.  And if that's what's needed to do a show, then that's what you have to do.  I'm just looking for a different solution. 
 
I wouldn't expect to do an event at a place without either doing a site survey FIRST (I try to do those anytime I can or money for travel allows) OR....asking some "detailed" questions on the phone or better yet, getting the bar or venue owner/manager to whip out their $600 Iphone and snap a picture of their power area.  And...get them to send a pic of the 50 amp plug in.  But even that won't guarantee great power so I would still have to be prepared but I would say that more times than not, if a place has had other entertainment in it and they've got a 50 amp plug and it's been used by that same entertainment over and over, it's probably acceptable to use for us.
 
But fortunately, that is why communication is key and "pre-planning" for events.  Which is why I'm at the stage (pun intended) of where I'm at now.  I want to have a better solution for power in "most" situations where we're doing larger shows.  The shows that still only require 2 or 3 wall outlets may not need a distro.  But when we want to step it up and have more, well, this would be it.
 
And yes, I've seen the Furman distros and I am considering them.  I'm also looking at some others as well.  There are many options.  But whether I have a qualified electrician build one or purchase one, it still only takes care of only one issue.  We still have to figure out cable length and size and proper hookups for most places. 
 
And as others have mentioned on here (which is a great point), if a qualified electrician builds one for us, more than likely, it won't be UL certified as a "whole" unit.  As such, I don't know if insurance would cover it in the event tha something happens and it is caused by the "homeade" distro.  In which case, I wouldn't be gaining anything then so it may be a wash anyway. ;)
Title: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Shane Ervin on January 29, 2013, 07:22:31 PM
Anyone care to chime in on the topic of bonding the neutral to ground at only point?

I was just on a gig where the PA Company's distro was placed in a situation where it was effectively a sub-panel, to a Show distro (upstream from this one).  Trouble was: the PA Co's panel had its neutral bonded to its ground, internally, reportedly.

Solution(s) = ?

A Motion Labs RAC PAC rack-mountable distro, for instance, will meter
- open circuit between
     chassis and the
     Neutral pin of twistlock

But
- a bond (low impedance connection) between
    chassis and the
    Ground Pin of twistlock

Reason for this practice would be a nice lead-in to a discussion on this very interesting topic with things like harmonic currents, k factor, Magnetic fields, hum... as well as some basic rules and guidelines to live by.  (e.g., single-bonded Neutral, avoid double-bonding).

At first glance, and for such a seemingly bland sub-topic of hydro power, this gets quite involved, but it's time well spent.  Careful planning can make for a safe, low hum deployment on each gig.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 07:23:41 PM
The text in bold is bullshit from a electrical engineering standpoint.  All the hot phase legs share a neutral and ground, and THAT is where you get your harmonic contamination.  Putting all of one type of load will likely insure that you have a very unbalanced loading situation that may exacerbate the neutral issue, not make it better.

We share power with lights all the time.  The relative noise levels are dependent on how well the dimmers are filtered and how many audio devices have the "pin 1 problem".  With ETC, Strand or Leprecon dimmers, we have zero noise.

At our new arena, each side of the upstage area has multiple service disconnects, but there is only one transformer serving each side.  To this day, I get road show guys that see separate switches and assume each has its own transformer... they don't, but for some reason the PA is quiet even though it shares the same 3 phase legs, neutral and ground with lighting, video, and automation.

As for building distros, in theory any competent industrial electrician can do it.  The reality is that either our insurance, or the client's insurance or the venue may require only *U.L. listed* distros, and that means the whole assembly, not just the components must be UL listed.  When it comes to purchasing distros, one will find most budget distros do not bear the UL sticker.

You know, I've had pretty fortunate luck with ground issues so far.  Sure, I haven't set up huge events yet but the larger ones I have done, I've been lucky enough to not have too many issues with a hum or buzz.  I don't know if that is due to having newer equipment or the places I have been at have had newer power supplies but my "hums or buzzes" have been pretty minimal.

And when I do have an issue, it has "usually" been because I've got a bad XLR cable or some other bad cable running along side something.  In some cases, it has been because I have simply plugged my laptop into a different plug in than I should have.  In other cases, it may have been because I was on the same circuit (breaker) in a bar where a neon was on or some other equipment was on behind the bar.  You know those damn ice machines or coolers. 

I've had a few situations where I couldn't get it figured out but not many.  It's usually a wiring issue on my part or picked the wrong outlet. 

In any case though, the hum & buzz has never been bad enough that it was noticable once I brought the slider up to 2% or 3%.  I which case, it is never even noticed by anyone other than me during sound check since once you get people into a building and are talking or getting ready to dance, they can't hear crap anyway.  ;D If I've ever had an issue THAT bad, I've been able to figure out it's a simple bad wire. 
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 07:29:08 PM
Using multiple outlets/circuits at unknown venues is often a recipe for ground loop problems and sometimes shock. You're on the right track looking for distro so long as you can actually plug it in. As far as distros go, I have no love for the Furman units and don't recommend them from prior experience with both the product and support. I will however recommend Motion Labs (http://www.motionlabs.com/c-32-rac-pac.aspx). They are industry standard and will pass inspection pretty much anywhere. They can build them any way you want or you can go with one of their "off the shelf" configurations. Prices are very reasonable as well.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 07:32:32 PM
Anyone care to chime in on the topic of bonding the neutral to ground at only point?

I was just on a gig where the PA Company's distro was placed in a situation where it was effectively a sub-panel, to a Show distro (upstream from this one).  Trouble was: the PA Co's panel had its neutral bonded to its ground, internally, reportedly.

Solution(s) = ?

A Motion Labs RAC PAC rack-mountable distro, for instance, will meter
- open circuit between
     chassis and the
     Neutral pin of twistlock

But
- a bond (low impedance connection) between
    chassis and the
    Ground Pin of twistlock

Reason for this practice would be a nice lead-in to a discussion on this very interesting topic with things like harmonic currents, k factor, Magnetic fields, hum... as well as some basic rules and guidelines to live by.  (e.g., single-bonded Neutral, avoid double-bonding).

At first glance, and for such a seemingly bland sub-topic of hydro power, this gets quite involved, but it's time well spent.  Careful planning can make for a safe, low hum deployment on each gig.

Shane, I'm all for this discussion but I would be taking notes as if you read my previous response, when it comes to grounds or lackthereof and/or their relation to "hums, buzzes & noises" (HBN if we want to simplify a term.....I'll patent it if need be... ;D ), I've been pretty fortunate that "most" of my issues have been figured out by moving a wire or plugging into different outlets.  I haven't had to deal with a large scale HBN isse though. 
 
That's not to say I'm not interested in it but just don't know.   Maybe it's not as noticable on a smaller scale with less power available and being sent to mains and stage monitors.  I don't know.  I've heard larger situations and seen other stage hands/sound guys running around trying to figure out where their HBN is coming from and feel for them but I've been fortunate I guess. 
 
But with the exception of simply using our equipment as intended and plugging them into the correct outlets with the correct plugs on them (not breaking off the ground plug), what can "most" people do in a matter of minutes?  If you're talking about an issue that is coming from the venue itself such as a bad ground from the incoming power supply from either the junction box or worse yet, further back (previous) to the box such as the incoming power line, then what can be done?   We can't fix the venue's power supply issues in a matter of minutes with a show ready to start can we?   :-X
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 07:33:48 PM
Anyone care to chime in on the topic of bonding the neutral to ground at only point?

Sure. Bonding at the service entrance or a newly derived service past the service entrance (aka transformer) are the only time you are allowed to bond neutral to ground. Any other place downstream is a code violation.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Scott Wagner on January 29, 2013, 07:41:34 PM
Using multiple outlets/circuits at unknown venues is often a recipe for ground loop problems and sometimes shock. You're on the right track looking for distro so long as you can actually plug it in. As far as distros go, I have no love for the Furman units and don't recommend them from prior experience with both the product and support. I will however recommend Motion Labs (http://www.motionlabs.com/c-32-rac-pac.aspx). They are industry standard and will pass inspection pretty much anywhere. They can build them any way you want or you can go with one of their "off the shelf" configurations. Prices are very reasonable as well.
+1
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 07:49:52 PM
Using multiple outlets/circuits at unknown venues is often a recipe for ground loop problems and sometimes shock. You're on the right track looking for distro so long as you can actually plug it in. As far as distros go, I have no love for the Furman units and don't recommend them from prior experience with both the product and support. I will however recommend Motion Labs (http://www.motionlabs.com/c-32-rac-pac.aspx). They are industry standard and will pass inspection pretty much anywhere. They can build them any way you want or you can go with one of their "off the shelf" configurations. Prices are very reasonable as well.

Greg, (and to others interested in distros)
Due to the previous research on this site and other sites, I have stumbled across many different distros and they each have a purpose.  Some are great but to be honest, many are simply more than I need and probably more importantly (for now anyway), out of my budget.  I want to get the right equipment but I can't afford a $1000 or $2000 (or more) distro when it is WAY more than I will need. 

Tim  (from other distro posts I read in doing my research here) had mentioned one company that may be what I'm looking for.  I'll post the link and if you look at the first distro in the link, that little distro may be all I'll need for now.  At least for 90% of my shows anyway.  Here it is:

http://www.ampshop.com/distro.html

For what I am looking to do, I would like to have one distro in a rack that would carry my 250' of feeder cable and power the first set of amps.  In which case, I would probably have the distro mounted in the same rack as the amps.  Yes, this would be a big rack but keep in mind, this would be for a larger show and a larger show isn't going to be done out of my little Ford Escort wagon (although I've done some nice little events out of that thing).  If I'm doing a larger show with something like dual 18's and 1 or 2 dual 15's (per side) 6 big speaker cabs aren't going to fit into an Escort Wagon.  Or my Chrylser minivan for that matter.  Although I can fit a lot in there, I can't fit 6 big speaker cabs AND amp racks in there.  Even if they did NOT have a power distro with 250' of feeder cable in it, they still aren't fitting. 

So......in these cases, I'm going to have a bigger vechicle like my trailer or a cube van/truck or bigger truck.  In which case, an amp rack that would have 2 or 3 good sized amps in it AND the distro with a case to hold 250' worth of feeder cable wouldn't take up much room. 

From there, for the other rack with amps, I would probably use the same type of power distro as in the top picture but without both 14-50R femal receptacles in it and only have the feeder cable going to the first power distro in the first rack.  Maybe I would though who knows?

The way I envision having this available would be to do two racks.  One rack for each side (or setup configuration depending on how I decide to set up events).   If I'm doing a smaller show with only dual 18 cabs and one dual 15 per side, then one rack would be all I need for the power required.  In which case, I would use the first rack with the big rack with 250' of power cable.  Even with this show, I'm still thinking I will need a good power supply that will require the use of this distro. 

But if I'm doing an even larger show where I'm doing 4 dual 18 cabs total (configuration dependent on what would be best for setup) and  2 dual 15's (or maybe 3 dual 15's per side) then I would use the additional amp rack as needed.

Of course stage monitors are included in both situations and that will be figured into the first amp rack.   
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 08:11:42 PM
Greg, (and to others interested in distros)
Due to the previous research on this site and other sites, I have stumbled across many different distros and they each have a purpose.  Some are great but to be honest, many are simply more than I need and probably more importantly (for now anyway), out of my budget.  I want to get the right equipment but I can't afford a $1000 or $2000 (or more) distro when it is WAY more than I will need. 

Lonnie. I purchased a Motion Labs 3RU Rack Pac several years back with the Hubble "California" 50A 120/240 inlet/pass-through & 4 30A twistlock 120/240 L14-30 circuits to distribute to smaller 2RU Rac Pacs in my amp racks and stage distribution. I paid less than $600 at the time. This is probably the one you want, same basic design but with regular 20A "Edisons" on the back:

http://www.motionlabs.com/c-83-50a-125250v-in-thru.aspx

Motion Labs products are ETL listed. I don't believe Amp Shop distros are listed by any agencies such as ETL or UL. That's not to say they're unsafe or not well made. But in some locales, inspectors want to see that on power distribution gear so they know it's been deemed safe by experts.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 08:28:44 PM
Lonnie. I purchased a Motion Labs 3RU Rack Pac several years back with the Hubble "California" 50A 120/240 inlet/pass-through & 4 30A twistlock 120/240 L14-30 circuits to distribute to smaller 2RU Rac Pacs in my amp racks and stage distribution. I paid less than $600 at the time. This is probably the one you want, same basic design but with regular 20A "Edisons" on the back:

http://www.motionlabs.com/c-83-50a-125250v-in-thru.aspx

Motion Labs products are ETL listed. I don't believe Amp Shop distros are listed by any agencies such as ETL or UL. That's not to say they're unsafe or not well made. But in some locales, inspectors want to see that on power distribution gear so they know it's been deemed safe by experts.

Greg, that is a pretty decent looking little unit.  Probably darn close to what I want. 

Anyway, I'll keep many options open and your point about whether or not they are ETL or UL listed or acceptable by code is a big thing to consider here.  Obviously that is what I want to make sure is going to be ok for my setups. 

Now, can anyone verify the length of 250' run being ok with either 4/4 or 2/4 SOOW cable? 

And while I'm on the subject, would it make more sense to have the cable be 4/5 or 2/5 so I could have it wired for 3 phase or not?  What is different at the power distro when needing to do 3 phase?  Are the components still built the same but when running into a 3 phase situation you have to change some wires around or is it a completely different junction box altogether?  I've read that the components are the same but you need to change the wiring (hence the additional wire for 3 phase vs. single phase).  I'm not too familiar with 3 phase nor understand it very well at all but I read on another distro post during my search on  here that someone ran into an issue when running 240 from a generator and when they switched to 208 3-phase, the issues went away. 

Can someone explain to me the advantages or disadvantages of 3 phase vs. 240 in simple terms? 

Sorry to ask so many questions but I'm hopeful that you'll be kind enough to offer your wisdom.  I think I've got a "fairly decent" handle on what I need to have done or what needs to be accomplished but just need to make sure. 
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 08:49:20 PM
P.S. - I've done 300' of 6/4 SO cord in a pinch with no issues. But I wasn't running lights, sound only. LED cans would have been fine though I'm sure.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 29, 2013, 09:03:11 PM
Yep, that's why I wanted to step up to something like this.  But, I want to make sure my investment will cover what I want to use it for.  If I buy a Peavey distro that says it's capable of 80 amps or a Furman distro that is either 100 or 120 amps, I want to make sure I can utilize them to their fullest potential.  Otherwise, I could EASILY spend $2000 or more on cable and distros to only end up with something that "still" won't be usable.  Or worse yet, not up to code.


Thanks for the reply Tom.  I appreciate the info so far.   :)
Yep I’m really sure that a NEMA 14-50R receptacle is a 50A circuit, not a 100A circuit.  That being said, you do get “100A” out of the circuit in the form of two 50A legs.

Yes I’m sure that code requires that a NEMA 14-series receptacle is fed with 4 wires – two hots, a neutral wire, and a ground.  This is a 240v/208v supply that can be broken out into two 120v “subcircuits”, if you will; in the case of a NEMA 14-50 these are two 50A circuits, totaling up to a potential 100A load at 120 volts.  This is ALWAYS (unless illegally installed) both a 240/208v and a 120v service.  There are not multiple ways to wire a NEMA 14-50.  If someone wired it to be “120v” by attaching both hot wires to the same phase in a  breaker panel, at best you’d gain nothing if both wires were tied to the same breaker, and at worst overload the neutral wire since you’d have two “ins” and only one “out”.

The Peavey and Furman distros are practically the same thing – 80A, 100A, 120A – different ways of speaking about the same thing,  subject to some de-rating in nomenclature to meet certain product guidelines, I suppose.  The Peavey distro has 6 20A circuits, totaling “120A out” in a manner of speaking, however only “100A (if you forgive the loose definition) are even available from the 14-50 plug.  I believe the Furman doesn’t come with a cordset, so theoretically you could put a 14-60 plug on it, though these are far less common than 14-50.

Subpanels almost always oversubscribe the service entrance of a building because there’s always headroom – nothing is ever 100% loaded, so there’s ample capacity to run 6 100A panels from a 400A service.  Restricting this to 1:1 (for general building – there are times when you must have a 100% supply and possibly even greater) would raise the cost of the electrical service, and add nothing.

Re: wire length -  Feel free to strongly disagree with general practice and experience, but I promise you there are reasons for not having a 250’ piece of 4/4 wire.  Just because you’ve seen it done doesn’t make it right.  Not necessarily in order of severity, reasons not to would include: accumulated heat in densely coiled extra wire creating a fire hazard, more voltage drop than necessary when you don’t need all that wire, PITA factor of wrapping 400lbs of wire, and cost.  Having a shorter pice of wire at the distro plus an extension cord or two are a lot smarter.  Folks that have 250’ pieces of wire generally have single-conductor SC cable, which has different rules.

Ampacity over distance:  It’s general convention to have your supply wiring not exceed 3% voltage drop over the run.  Since the whole circuit is considered, that’s 500’.  3% of 120 volts is 3.6v.  For a 50A load, we’re allowed a resistance of .072 ohms.  Dividing that by 500’ means we need wire with  a resistance of .000144ohms/ft.  2ga wire is .0001563, 1ga is .000124.  You could probably get away with 2ga wire and have slightly more than 3% voltage drop, but that’s a long run.

RE: UF vs SOOW again – UF is not much smaller than SOOW.  The actual wire is the same cross-sectional area.  The insulation may be slightly different.  I also doubt the cost is much different.  Your links are for 10/3 wire, which is much cheaper than 4/4.

You don’t want 3-phase at this point.  You can use a single phase (split phase) distro from a 3-phase supply, but not easily the other way around.  Start with a 14-50 system and when you out grow it you can think about 3-phase.

Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 29, 2013, 09:10:21 PM
P.S. - I've done 300' of 6/4 SO cord in a pinch with no issues. But I wasn't running lights, sound only. LED cans would have been fine though I'm sure.
I'm sure it worked passably at less than full load, but being clear on this, 6/4 cord isn't allowed for 3 current-carrying conductors by the letter of the NEC at any distance, much less 300'. 

I'm aware that some inspectors will pass a 6/4 system at 50A, but IMO this is foolish for two reasons:

1. we're all worried about UL/ETL listing for the distro hardware; if that's a concern, then so is marginal supply cabling.

2. Skimping on feeder wire reduces rig performance.  We spend thousands of dollars on high-tech PFC and whatnot amplifiers to squeeze every last watt from our electrical supply.  Negating this by undersizing the feeder to save a few bucks is just dumb, and we only cheat ourselves.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 09:24:57 PM
I'm sure it worked passably at less than full load, but being clear on this, 6/4 cord isn't allowed for 3 current-carrying conductors by the letter of the NEC at any distance, much less 300'. 

I'm aware that some inspectors will pass a 6/4 system at 50A, but IMO this is foolish for two reasons:

1. we're all worried about UL/ETL listing for the distro hardware; if that's a concern, then so is marginal supply cabling.

2. Skimping on feeder wire reduces rig performance.  We spend thousands of dollars on high-tech PFC and whatnot amplifiers to squeeze every last watt from our electrical supply.  Negating this by undersizing the feeder to save a few bucks is just dumb, and we only cheat ourselves.

You are correct TJ. It was in a pinch, and one time many years ago. I definitely don't recommend it. Average draw was probably under 20A so it was usable for that moment. Had lighting been involved it would have never worked.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 09:25:27 PM
P.S. - I've done 300' of 6/4 SO cord in a pinch with no issues. But I wasn't running lights, sound only. LED cans would have been fine though I'm sure.

Greg, you just deleted what you previously wrote by editing your comments.  Shoot man.  If you can remember what you said, please put them back up for all to see. 

Anyway, I am familiar with the voltage calculator and if I go in and put the specs in as follows:

Source:  240V
Cable size:  4 awg (70/55A)
Load current in amperes:  60 amps
System type:  AC single phase 60 Hz (assuming that's what 240 volt single phase is.  The only other options are DC or 3 phase and those aren't it.)
Conductor type:  copper
Conductor temperature:  90C (194F)
Conduit type: No conduit  (The only other options are PVC, aluminum or steel and I guess I could use PVC as a similar conduit to the SOOW jacket but I used none to start.  I will use PVC as well and see what happens.
Select parallel runs:  single set of conductors (since I'm not considering 3 phase at this point, I'm just choosing this option.  I will select 3 phase as well and see what changes)
Length of cable:  250
------------
Estimated voltage drop:  4.1%

---*(now, I put in 60 amps as a "worst" case scenerio for the type of load I "could" be pulling at a time.  Perhaps it wouldn't even be possible and the breaker at the power source would trip before it got to this point but I wanted to put that in to see what the results would be.  According to the calculations, it's still within the limits of 5% or under.  Also, I used a higher temperature for the cable as I could assume that the cable would get hotter under the given load for the length of cable if I was to consume that much power through it.  Again, I can put it to lower specs and get better results and will post those unerneath this message)*--

If I change my specs to be ONLY 50 amps AND ONLY 75C(167F) temperature AND use PVC as a conduit, the voltage drop goes down to only 3.3% at 250 feet with 4 gauge cable.  So, it's still well within the limits. 

Changing the gauge of wire to 2 gauge instead of 4 drops the voltage drop to around 2% at 50 amps and 2.4% at 60 amps so obviously that would be a benefit but it would be negligable considering the amount of money that would be spent on cable to go from 4 gauge down to 2 gauge. 

Changing the conduit had not effect on the voltage drop (which I assumed it wouldn't unless the temps get really high and then I suppose it would change things but I am not considering temps to be that high).

By putting in 3 phase numbers into the calculator, the voltage drops were even more significant and reduced it by 1/2% or more.  So, considering my "worst case scenerio" by my first numbers I put into the calculations, having 4 gauge wire at 250' is well within limits even at 60 amps of power.  Which would virtually never be happening.  At least I'm "assuming" it can't but maybe someone can come on here and tell me if I'm wrong or not.  Well, I know that in a few cases, the amps can draw more power than that overall but that is with super duper heavy bass lines at a constant rate and we know that those tones are virtually unattainable for long periods of time in the live music or DJ music scene.  At least for "most" shows I think.

***I put in 300 feet at my same first specs and it came back with 4.9% voltage drop so even that would be acceptable according to the information I'm gathering off of the voltage calculator site.  Obviously, having only 50 amps in the specs vs. 60 is even better.***


As for running lights, I don't own old style par cans and never will.  I mainly own LED fixtures with even some moving head fixtures that are LED.  I have some moving heads with traditional arc lamps or other lamps and other lights but for the most part, my lighting is LED and DMX controlled so I don't have dimmer packs and so on to worry about.  So, the power draw for lighting is not the same as it was back in the day and that helps a lot.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Greg_Cameron on January 29, 2013, 09:36:13 PM
Greg, you just deleted what you previously wrote by editing your comments.  Shoot man.  If you can remember what you said, please put them back up for all to see. 

Ah crap, that was an accident. Sorry about that.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 10:11:59 PM
Yep I’m really sure that a NEMA 14-50R receptacle is a 50A circuit, not a 100A circuit.  That being said, you do get “100A” out of the circuit in the form of two 50A legs.  Okay, so I guess I'm partially correct in my thinking and partially wrong.  I assumed that if they do provide two separate 50 amp legs that they are adding up to be 100 amps at the distro.  Right?  Which would mean that 100 amps would be available at the distro right?  One leg of the junction box would have 50 amps of 120 volts and the other would have 50 amps of 120 volts correct?  But if that is the case, why are they still rating it as a 50-amp outlet/service?  That just seems odd to me.  Again, sorry for the questions but just trying to get clerification.   And I understand that maybe this is a little more complicated than I understand but that's why I'm trying to get a handle on it. 

Yes I’m sure that code requires that a NEMA 14-series receptacle is fed with 4 wires – two hots, a neutral wire, and a ground.  Okay, I didn't know if a person was allowed to hook it up with only one hot to one side or the other (which would provide the single 120 volt 50 amp service) and not hook up the other side (at all) and then have the neutral and grounds hooked up.  In which case, there wouldn't be a 4th wire at all and ONLY the 3 wires.  This is a 240v/208v supply that can be broken out into two 120v “subcircuits”, if you will; in the case of a NEMA 14-50 these are two 50A circuits, totaling up to a potential 100A load at 120 volts.  Like I thought right?  This is ALWAYS (unless illegally installed) both a 240/208v and a 120v service.  Now see, this is where you confuse me again.  First you say that a 14-50R receptacle has to be fed with 4 wires.  In which case, would this HAVE to be 240 volt service?  If it's being fed 4 wires, where is only 120 volt service coming into play?  By saying "and" 120v service, to me, it seems like they could choose to wire it up by either using 4 wires for 240/208 OR 3 wires for only 120.  What am I missing here?  There are not multiple ways to wire a NEMA 14-50.  If someone wired it to be “120v” by attaching both hot wires to the same phase in a  breaker panel, at best you’d gain nothing if both wires were tied to the same breaker, and at worst overload the neutral wire since you’d have two “ins” and only one “out”.  I'm not referring to if someone were to wire it up this way by using 2 hots on the same connection.  I'm referring to "if" someone wired it up to use ONLY 1 hot on one connection, the ground, and then the neutral AND NOT use a 4th wire at all.  In which case, isn't this where we would get our option to have ONLY 120 volt service out of this plug?  And....in which case, if we wired our plug to be 240 with 2 hots (one on each side as you're supposed to), then in either case, we would (at minimum) be guaranteed 120 volt service at these places?  Again, am I just completely way off here?

The Peavey and Furman distros are practically the same thing – 80A, 100A, 120A – different ways of speaking about the same thing,  subject to some de-rating in nomenclature to meet certain product guidelines, I suppose.  The Peavey distro has 6 20A circuits, totaling “120A out” in a manner of speaking, however only “100A (if you forgive the loose definition) are even available from the 14-50 plug.  Right, and this probably references the fact that even though there are more plugs available than power for each plug, it IS BECAUSE the power is never used to full capacity at any one time by the equipment being attached to the plug (like you mention later on in this post).  I think I understand that.    I believe the Furman doesn’t come with a cordset, so theoretically you could put a 14-60 plug on it, though these are far less common than 14-50.  Yes, you "could" put a 14-60 plug on the Furman distros but like you said, those seem to be pretty rare for most places so what would be the point then?  Again, I suppose it would be best to have an interchangeable twist lock end so "if" you needed a different end for either wiring direct or using a 14-50 or 14-60 plug, you could simply have someone make you an end for that 14-60 plug when it was needed.  But I can't foresee that happening anytime soon since most places don't have that.

Subpanels almost always oversubscribe the service entrance of a building because there’s always headroom  Okay, I get that. – nothing is ever 100% loaded,  Okay, I get that too so there’s ample capacity to run 6 100A panels from a 400A service.  Now it makes sense when I now understand that at no time will ALL 6 separate 100 amp panels be sucking 100 amps out of eaach one at the same time.  Meaning, they will ALL be distributing the loads that will be "under" that 400 amp rating.  But, if for some odd reason they were to spike into using more than the allowed 400 amps evenly, it would simply trip the 400 amp breaker.  Correct? Restricting this to 1:1 (for general building – there are times when you must have a 100% supply and possibly even greater) would raise the cost of the electrical service, and add nothing.  Gotchya.

Re: wire length -  Feel free to strongly disagree with general practice and experience  Not trying to disagree completely Tom, just trying to get clarification.  I'm just going by the voltage calculator and want to hear your experience as well, but I promise you there are reasons for not having a 250’ piece of 4/4 wire.  Just because you’ve seen it done doesn’t make it right.  Okay.  That's kind of where I'm concerned.  Not just for me but what about other places that do use it?  I don't want to be a taddle tail but if they are using it, how can it be acceptable by code?  But again, depending on load, it probably is ok right?  In which case, as long as the load is not too much, then it would be acceptable right?  Not necessarily in order of severity, reasons not to would include: accumulated heat in densely coiled extra wire creating a fire hazard, more voltage drop than necessary  (is the voltage drop calculator incorrect with their figures?  I'm not trying to be a jerk here but am I supposed to go by that calculator or something else?  If that calculator is incorrect, then would someone tell them it is and can I get the correct information from a different site that has accurate information?  I'm simply going off of what that site stated as I am sure it is "supposed" to be accurate.  If it isn't, then tell me please.  If I'm trying to get the correct information from a site that claims to be accurate, how can I know better if I'm a novice?) when you don’t need all that wire  Now wait a sec...how do you know I won't "need all that wire?", PITA factor of wrapping 400lbs of wire  Yes, I realize the pain in the ass...I get it.  I'm not concerned about that., and cost  I agree the cost will be a lot but it may be within my budget.  I don't know yet and we'll see if I think it's worth it.  But cost isn't really the issue at this point.  At least with "some" things.  Having a shorter pice of wire at the distro plus an extension cord or two are a lot smarter.  Okay, so explain to me how having multiple pieces of "an extension cord" changes what I'm talking about overall anyway?  If I need 250' of a run, I need 250' of a run.  The length doesn't change, only the weight.  And I said that wasn't a concern.  The price doesn't change because two 100' cables and one 50' cable is going to cost more than 1 single 250' cable.  Having 2 or 3 cables in between that run doesn't seem to make sense to me if I could easily have one long cable AND NOT have to spend extra for the added expense of additional plugs and recetacles.  And what about the "potentially" added resistance that would be put into the equation by having multiple connection points.  That has to be taken into consideration too doesn't it?  Why spend extra money for added plugs and receptacles?  The cable length is still going to be the same.  Plus, if a 250' cable can work for a 50' run (which it can) why limit yourself to ONLY having a 50' cable when you need a 100' or 150' or 250' cable for more runs in between 0 to 250'?  In those cases, you have to either rent or purchase your own cable for the additional run and then we're back to what I'm talking about with the initial investment.  I don't understand where I'm actually gaining anything by having multiple cables with multiple plugs and receptacles added onto the cable. Folks that have 250’ pieces of wire generally have single-conductor SC cable, which has different rules.  I don't know what you're referring to here but please elaborate.  I'm interested.

Ampacity over distance:  It’s general convention to have your supply wiring not exceed 3% voltage drop over the run.  So the 5% rule limit is too much?  Okay.  Since the whole circuit is considered, that’s 500’.  I only need 250'.  Maybe 300' at max.  3% of 120 volts is 3.6v.  For a 50A load, we’re allowed a resistance of .072 ohms.  Dividing that by 500’ means we need wire with  a resistance of .000144ohms/ft.  2ga wire is .0001563, 1ga is .000124.  You could probably get away with 2ga wire and have slightly more than 3% voltage drop, but that’s a long run.  Again, I know the run is long.  But if it is the best option financially for the long run (more pun), then that is what I want to consider. 

RE: UF vs SOOW again – UF is not much smaller than SOOW.  The actual wire is the same cross-sectional area.  The insulation may be slightly different.  I also doubt the cost is much different.  Your links are for 10/3 wire, which is much cheaper than 4/4.  Yeah, I don't know if the 250' 10/3 UF wire I listed is good for  50 amps or not.  It says 600 volts and I had talked to someone at one time that said it "may" be "possible" but again, that is completely different than be acceptable by many codes and I don't want a show to get shut down because of that.  So, if UF won't work, then it won't work.  I just thought if it was an "option" then it would be worth considering.  Especially since the cost is about 20% of the 4/4 SOOW cable.  Or 15% of a 2/4 SOOW cable.

You don’t want 3-phase at this point.  You can use a single phase (split phase)  Huh???...I'm lost on this now.  Do you mean 2 separate 120 volt "legs" off of a 240 volt system or something else? distro from a 3-phase supply, but not easily the other way around.  So, if I have 4/5 cable for 3 phase and buy that for my distro that wouldn't be a good thing for the "potential" future use of doing 208/3 phase service?  Again, although the additional cable will cost a little more and yes, it will add more weight, if it is something that could be used in the future for 3 phase service, I would rather consider that now while I'm considering spending $1000 on cable.  If I spend $1000 on cable and need to upgrade to a different cable of 250' that allows 3 phase service, I will have to start all over and buy a 4/5 cable as opposed to a 4/4 cable to allow for the 3 phase service.  In which case, my 4/4 cable wouldn't be capable of doing 3 phase so it wouldn't be as good of an investment right?  Kind of like "headroom", better to have it than not wouldnt' it?  That way, when (or "if) I need it, it's there ready to go correct? Start with a 14-50 system and when you out grow it you can think about 3-phase.  Yeah...you're probably right.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 29, 2013, 10:12:53 PM
Ah crap, that was an accident. Sorry about that.

You're an accident (twss). 

Sorry, I couldn't resist.   :o
Title: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Brian Larson on January 30, 2013, 02:36:14 AM
You can't just buy 5 conductor wiring and all of a sudden have a three phase system. The 14-50 plug you're talking about only has 4 pins. The only way to do high ampacity three phase is with single conductor wire and camlocks. In this scenario you would have five individual cables (three hots, ground, neutral) with five individual camlock connectors on each end. This solution is VERY EXPENSIVE AND VERY HEAVY. Honestly it doesn't sound like you'll need this even in the future.

DO NOT MAKE A 250' LENGTH OF CABLE. YOUR EMPLOYEES/BACK WILL HATE YOU. Also, what was already said, leaving it coiled up will create an induction loop which could melt your cables and cause a fire so
even if you only need 20' for a certain gig, you'll still have to unroll the other 230'.

As for the calculator website not being accurate... The people on this site are professionals. They know more about this than you or some calculator. Listen CAREFULLY to what they're saying.


Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Ray Aberle on January 30, 2013, 03:11:11 AM
Now see, this is where you confuse me again.  First you say that a 14-50R receptacle has to be fed with 4 wires.  In which case, would this HAVE to be 240 volt service?  If it's being fed 4 wires, where is only 120 volt service coming into play?  By saying "and" 120v service, to me, it seems like they could choose to wire it up by either using 4 wires for 240/208 OR 3 wires for only 120.  What am I missing here?

It IS 240volt service, that has 120volt available as well. The 240volt refers to the two hots, a neutral and a ground. You can then connect any 120volt device to a panel fed by the 240 service, and it will feed from one of the hots, the neutral and the ground.

In other words, if you were to look inside a standard electrical panel (in your house, for example), you have 240volt service coming from the street (unless you are pimping and have 3Ø service at home... I'd be jealous.). That comes in as two hots and one common (neutral) line. The grounding bar on your home panel is fed from the earth ground. So, 200A/240V gives you two hots, and when you look down the panel, "every other" breaker is set to access one leg or the other. When you install a 240volt breaker, you know how it's two poles, connected together? Since it's side-by-side, the two hots it gets are automatically split between the two legs.

So, your house has 240volt coming in, but provides 120volt service to all of the branch circuits by the nature of landing the hot on one leg or the other. (Except for your 220volt appliances, range, maybe dryer, hot water heater, hot tub, heaters.)

The 50A circuit (NEMA 14-50) is rated as a 50A circuit because that's what the breaker is. Even though it's providing "100 amps" as in 50A on each leg, it's still a 50A breaker, because either leg will trip if you try to pull more than 50A.

To address one of your statements-- if someone wired the plug with just one of the hots (let's say X is connected and Y is not), when you connect YOUR range plug to the outlet, half of your system will not work, because the half of your panel/distro (in this scenario, the Y leg) that relies on the Y connection will see-- nothing. Your panel/distro NEEDS to see current on BOTH legs to not only avoid overloading the upstream breaker but also to fully utilize the connections that it provides.

As for the code adherence by others-- and your wondering why others are doing it-- well, the responsibility for proper electrical procedures and safety lies with one person: YOU. You cannot always change or dictate what others do, but you have the ultimate responsibility to make sure that every part of the production that you are involved with is carried out with the utmost professionalism and attention to safety.

What Brian mentioned about cam feeder is what was mentioned with "single conductor cables." You're looking at things like http://www.lexproducts.com/cs/entertainment_product?id=350&market=Entertainment&productLineId=17&subCategoryId=93 whereupon you have five lines running from the source (panel tie-in, camlok access points at the panel, or hardwired to a generator). That's a three-phase feed, and until you reach that point, don't worry about it. I've 200' of 1Ø #2 wire, and it's super friggin' heavy, so that's why people are warning you away from hauling around a 250' length of cable. For my 50A applications, I don't have anything longer then 100' -- partially for the voltage drop, but also partially that it's a pain in the butt to coil/uncoil even 100' at a time. I'd rather add a 50' length to a 100' length then deal with one 250' length.

By the way, "split phase" is used to mean the same as "single phase," it's referring to two legs as opposed to the one phase. "Phase" refers to the degrees of separation between the two legs-- X to Y is the same as Y to X; X to Y is different then Y to Z, which is still different then Z to X.

You asked about getting, say, 4/5 as opposed to 4/4 now-- several things here:
- Once you go to 3Ø for main feeder cable, I NEVER see it that small (#4 wire) of a cable... everything is 100A to 200A service, which requires at LEAST the #2 cable.
- You can connect a single phase distro to a 3Ø service, but you can't connect 3Ø distros to a single phase service. Same concept as before when discussing why a NEMA 14-50 plug with only one hot connect will cause trouble with your 240V distro-- you connect the 3Ø distro in and one of the legs will be absent!

Electrical sure is fun, isn't it?!? :D

I hope I answered your major questions; let me know if there's something that is still confusing!

-Ray Aberle

Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 30, 2013, 03:47:58 AM
You can't just buy 5 conductor wiring and all of a sudden have a three phase system.
 
Well, I know it isn't "that" simple but to have a 3 phase setup, am I wrong in understanding that you do indeed need 5 wires instead of only 4 for it?  I understand that there would be some different wiring at the supply end (the venue or bar or gym's power center/junction box) and I wouldn't be the one to hook that up but, if the same 5 wire cable is used for 3 phase that would be used for a single phase setup for 240 like I'm talking (minus the 1 wire and only need 4 for 240 single phase), then why not have the additional cable for future needs?  Even if I don't "need" it, it's there if I do correct?  The 5 wire setup with 4 gauge is the correct wire for 3 phase is it not?  At least considering that I would be going 200 to 250 feet it would be 4 gauge.  Less distance would be smaller gauge obviously. 
 
The 14-50 plug you're talking about only has 4 pins. 
 
I understand this and I wasn't implying that 3 phase is run out of this same connector.  To my knowledge, wiring for a 3 phase setup is different.  However, I do believe I read somewhere that some people have been able to wire 3 phase out of those type of connectors and that some places have wired them up to be 208/3 phase.  At least I am pretty sure I read that somewhere.  Maybe I'm wrong.  But either way, I wouldn't be wanting to have it wired for 3 phase UNLESS it was needed.  In which case, I would be getting in touch with someone who understands this.  In any case, I just want to be prepared.
 
The only way to do high ampacity three phase is with single conductor wire and camlocks. 
 
Okay, I wasn't aware that ONLY camlocks can be used for 3 phase.  Is this code and standard or just what is "typically" done?  So nobody has ever done 3 phase without camlocks?
 
In this scenario you would have five individual cables (three hots, ground, neutral) with five individual camlock connectors on each end. This solution is VERY EXPENSIVE AND VERY HEAVY. Honestly it doesn't sound like you'll need this even in the future. 
 
Again, I agree that "more than likely" you're correct and I won't.  But I just don't want to kick myself in the future when I could have had this available early on and run into an issue somewhere.  Maybe I never will.  I don't know.  I suppose if I just plan on either 240 single phase with the 50 amp 14-50R plug as I'm discussing OR using standard wall outlets for my events, then I won't have to concern myself with 208/3 phase.  Again, I'm just trying to think ahead and be prepared. 

DO NOT MAKE A 250' LENGTH OF CABLE. YOUR EMPLOYEES/BACK WILL HATE YOU. 

 
Well, I guess I'll just have to hate myself then since I would "most likely" be the one setting up the shows along with some assistants in some cases.  And when I do have assistants, well....I guess since I've already discussed with them the necessity to be able to lift heavy objects such as cases, equipment, and yes, cables, maybe that is alreay covered.  But again, if this is something that I have to do myself, then so be it.  But let's be honest here, it's not like "nobody" has a long cable that has to be run.  Others have been doing it for years so it's not like I'm asking people to do something that's never been done.  And even if I was, does that make it wrong?  Hey, don't get me wrong, I want to save my back and my employees' too but come on, we're in an industry where we NEED to be able to lift heavy things.  So, somebody has to do it. 
 
Also, what was already said, leaving it coiled up will create an induction loop which could melt your cables and cause a fire 
 
Now THAT is an excellent point and one I forgot about and makes unbelievably great sense.  In which case, maybe it would be better to have two separate 100' cables and leave a 50' cable attached to the distro.  Or a 100' cable to the distro and two 75' cables.  Either way, the issue about heat and fire is an excellent point. so
even if you only need 20' for a certain gig, you'll still have to unroll the other 230'. 

 
Like I just said, damn good point to be safe. 

As for the calculator website not being accurate... The people on this site are professionals. They know more about this than you or some calculator. Listen CAREFULLY to what they're saying. 

 
I am listening and taking notes.  Don't confuse my questions with a simple concern about accuracy and/or clerification.  Here's the thing, I wouldn't have asked the questions if I already knew the answers.  So, I think it's obvious that I want to get the correct information.  But as I said, who am I supposed to believe for accurate information?  I know that is something that each individual has to decide for themselves and I want to take the knowledge of many trained pros here as very good information.  But, am I to consider that information off of that "wiring calculator" as NOT accurate?  In which case, then how do I know what is and what isn't accurate?  I don't know people on here from Adam so I have no idea what credentials people have in telling me what they are.  But I am hopeful that I am getting accurate info.  But if one person suggests to use that site's calculator for a reference and another person does not, then who am I to trust?  Do you understand the confusion there?

Hey everyone, I beg you not to take my comments the wrong way.  As mentioned on another site that I've asked this same question on, while I was doing research for distros on there, somebody made a VERY GOOD point about when people ask questions like these and then the comments made regarding them.  We NEED to consider that ANYONE reading these posts may be a brand new "newbie" that has no idea what we're talking about.  As such, it's important not to be throwing around "suggestions" unless you know yourself that they work.  And if they are different than code or what's "standard" or "acceptable" please state why what you did was ok for you.  Or at the very least, if you are to make a suggestion that is not "typical" in the setup, at the very least make a warning about what it is you did so the newbies don't get the wrong idea. 
 
As people have said, you never know who could be reading and then go and do things that we discuss on a regular basis without knowing any better simply because they read it on a forum.  Sure, we should "know better" than to take this stuff as gospel but some may do just that.  And actually, that's "sort of" the reason I posted my question.  I've seen and heard a lot of stuff but just because I've seen it done does NOT make it right or acceptable by codes, safety, and so on.  I would rather do things right and that's why I'm questioning the way I've seen it done in the past. 
 
Maybe those shows were doing it wrong and shouldn't have been doing things the way they were.  I don't know. 
 
An example would be the post that Greg had regarding using a 6/4 SOOW cable for a 300 foot run "in a pinch."  Now although it wasn't stated specifically, I think Greg's mention of "in a pinch" should tell someone that was reading this that this his "in a pinch" solution was probably not the best option.  To me, "in a pinch" has a warning in front of it.  But if others can't understand that, then that's their fault.  Perhaps it should have been stated to everyone "not to try this at home" as it will not pass code, isn't something you "should" do due to added load (power) requests on the cable which could potentially cause issues with heat and yes, potentially fire.  I suppose that should have been said.  I thought it "sort of" was implied though.  Probably among a few other things regarding that particular situation.  But even though Greg "got by", it may have still been up to code for all we know.  (I don't know).  In which case, if it is up to code, then that's a good place to start.   
 
So, I guess what I'm saying is that as I read the comments, suggestions, and experiences from other people, I am hopeful that UNLESS OTHERWISE STATED, they are making these comments with the understanding that what they say could be taken as good information.  Afterall, if you're going to make a comment, I hope you're not doing it with the intention to mislead anyone of put out false information.  If you are, then what good does that do other than cause people to do the wrong things?  Of course, that's where others need to come in and make sure that somebody isn't making a bad suggestion.  Which has been done on this post a few times regarding wiring and connectors and so on.  (No Greg, I'm not trying to call you out one bit because you probably have the knowledge to know what you were doing in your particular situation and could request only 60% or 70% of the load that the wire could handle and make it acceptable). 
 
One thing I know that has been said constantly over and over on every single forum is the mention of getting a "qualified electrician" to do the work.  I don't think anyone disagrees with this and I don't think that this is something that doesn't cross a person's mind when considering these things.  Maybe it doesn't.  I don't know.  But I just can't see someone that has no more knowledge than being able to plug in an outlet to a standard wall outlet trying to tie into a junction box with bare cable ends or trying to hook up cam locks or hooking up transformers for huge events.  In which case, I think pretty much everyone knows that getting an electrician to do the work is paramount.  So isn't the whole "get an electrician to do it" pretty overstated?  It's a given. 
 
But regarding the word "qualified", I'll bet there are tons of you on here that have WAY...WAY more knowledge than even some veteran electricians of 30 or 40 years when it comes to this stuff.  After all, a lot of veteran electricians are used to wiring up houses at best and maybe a lot of them are just doing typical outlet wiring in a home and not even messing with incoming power and wiring up junction boxes.  Maybe their just reserved to wiring outlets and putting in some breakers.  (Which a lot of people can do).  I'll bet a lot of electricians don't even have a clue what we're discussing here.  And I know this to be true by discussing this with a few of them because you know what some of them say when I ask them about some of these things?....."You need to talk to a production electrician." 
 
It's like asking a "general practice" doctor to diagnose cancer or a fungus that they have no clue how to because they are skilled in "general" diagnosis for "most" patients.
 
Well, as you know, we (this industry) are not "most" patients right?
 
So, I'm coming here to get industry specific questions answered (hopefully) by people I feel probably know a thing or three.  At the same time, I'm trying to learn and just want to back up statement or comments with facts and accurate info.  I hope that's not wrong.   ;)   
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Ray Aberle on January 30, 2013, 04:00:56 AM
Okay, I wasn't aware that ONLY camlocks can be used for 3 phase.  Is this code and standard or just what is "typically" done?  So nobody has ever done 3 phase without camlocks?

That's not what Brian said. He said, specifically, "HIGH ampacity three-phase." In my rig, I use Motion Labs rack packs to service my amplifier racks. I have both 1Ø and 3Ø units; the 1Ø units take an L14-30 220V/30A twist lock connector and the 3Ø units take an L21-30 208V/30A twist lock connector. The service cables are 8/5 (or 10/5, depending on who is providing the cabling) multi conductor single jacket cables.

What was being referred to was running 100A/200A/400A input from a mains service to your distro; that's where you see the multiple single conductors with camlok connectors. The other advantage of going with single conductors is that they'll lay flat as opposed to a huge cable trying to hold everything together. When you're running service across large areas with cable ramps, you really want the individual conductors to be able to flow through each channel of the ramp!

Ray
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 30, 2013, 04:32:06 AM
It IS 240volt service, that has 120volt available as well. The 240volt refers to the two hots, a neutral and a ground. You can then connect any 120volt device to a panel fed by the 240 service 
 
Well...as long as that 240 is broken down to two separate legs of 120 right?  Obviously you can't just go hooking 120 volts to a 14-50R 240 volt female connector since there aren't plug ins that allow this.  (which is a good thing).  , and it will feed from one of the hots, the neutral and the ground.
 
Gotchya.  Makes sense now.

In other words, if you were to look inside a standard electrical panel (in your house, for example), you have 240volt service coming from the street (unless you are pimping and have 3Ø service at home... I'd be jealous.). That comes in as two hots and one common (neutral) line. The grounding bar on your home panel is fed from the earth ground. So, 200A/240V gives you two hots, and when you look down the panel, "every other" breaker is set to access one leg or the other. When you install a 240volt breaker, you know how it's two poles, connected together? Since it's side-by-side, the two hots it gets are automatically split between the two legs.

Ok, got that now.
So, your house has 240volt coming in, but provides 120volt service to all of the branch circuits by the nature of landing the hot on one leg or the other. (Except for your 220volt appliances, range, maybe dryer, hot water heater, hot tub, heaters.)

Yep, understood.

The 50A circuit (NEMA 14-50) is rated as a 50A circuit because that's what the breaker is. Even though it's providing "100 amps" as in 50A on each leg, it's still a 50A breaker, because either leg will trip if you try to pull more than 50A.

Okay, I am pretty sure I understand the 50 amps on each leg that would equal a total of 100 amps in the distro (50 on each leg as stated) but, are you saying that if we pull more than 50 amps from the distro's legs combined or just if we pull more than 50 amps from "each" individual leg?  ---Follow me here----I've got this 240 coming in as 120 volts with 50 amps on each leg (as has been described very well now) and on "EACH" leg I've got say 3 separate 20 amp breakers and from there, I've got a pair of 20 amp outlets on each breaker.  Now, say I've got 3 of my amps hooked up to each outlet therefore one plug in on each outlet is not used.  So, we're using a total of 3 plug ins for the 3 amps.  Now, let's say that I'm running these amps hard and they are pulling close to 18 amps each (let's just say for arguement's sake they are ok)....in this case, if ALL 3 amps are pulling 18 amps at once (together), then this would be 54 amps total JUST ON THAT ONE LEG.  So, in this case, the 50 amp breaker either in the distro or the one back at the power supply should trip correct? 
 
If yes, that makes sense. 
 
But hear me out on this one.  Let's say I have the same exact set up on the other leg with 3 separate dual 20 amp outlets and I have the same 3 amps plugged into them.  --HOWEVER....this time all 6 amps are only pulling 15 amps at one time (all together).  Which would equal a total amp pull of 90 amps on the distro (45 on one leg and 45 on the other).  Since it's only 45 amps per side, will the breaker still be ok and not trip OR will the breaker pop since it's pulling a total of more than 50 amps? 
 
If it is no, the breaker will not pop, then I understand.  However, if it is yes, the breaker will trip, then I am confused. 
 
If you're explaining to me that the distro can NOT have a "TOTAL LOAD" *(between both legs) at any given time of 50 amps or more then I don't understand why they make 2 separate 50 amp services available to total up to 100 amps if 100 amps isn't actually available at a given time. 
 
I understand the load fluctuation and the need to distribute the load and that "most" times the distro may not see a total load of more than 45 amps so it wouldn't be an issue.  But I can't imagine that with running some of this high powered sound equipment along with older lights that consume high amounts of power that limiting them to only 50 amps (total) is what's happening. 

To address one of your statements-- if someone wired the plug with just one of the hots (let's say X is connected and Y is not), when you connect YOUR range plug to the outlet, half of your system will not work, because the half of your panel/distro (in this scenario, the Y leg) that relies on the Y connection will see-- nothing. Your panel/distro NEEDS to see current on BOTH legs to not only avoid overloading the upstream breaker but also to fully utilize the connections that it provides.  Although it would put a load on the upstream breaker, wouldn't one side of the distro still work?  Or since the neutral can't switch back and forth (I'm not sure about this in single/split phase) will it not work at all?  The side that I plugged into with the 20 amp breakers would still work since power is coming into that leg wouldn't it?  I'm not talking about "ideal" situations here but what would "actually" happen.  *(Again, this wouldn't be recommended kiddies)* 

As for the code adherence by others-- and your wondering why others are doing it-- well, the responsibility for proper electrical procedures and safety lies with one person: YOU. You cannot always change or dictate what others do, but you have the ultimate responsibility to make sure that every part of the production that you are involved with is carried out with the utmost professionalism and attention to safety.

Understood and that's why I'm here asking the questions.  I would like to do things the right way and not necessarily "the way I've seen it done."
What Brian mentioned about cam feeder is what was mentioned with "single conductor cables." You're looking at things like
http://www.lexproducts.com/cs/entertainment_product?id=350&market=Entertainment&productLineId=17&subCategoryId=93 (http://www.lexproducts.com/cs/entertainment_product?id=350&market=Entertainment&productLineId=17&subCategoryId=93) whereupon you have five lines running from the source 
 
Gotchya.
 
(panel tie-in, camlok access points at the panel, or hardwired to a generator). That's a three-phase feed, and until you reach that point, don't worry about it. I've 200' of 1Ø #2 wire, and it's super friggin' heavy, so that's why people are warning you away from hauling around a 250' length of cable. For my 50A applications, I don't have anything longer then 100' -- partially for the voltage drop, but also partially that it's a pain in the butt to coil/uncoil even 100' at a time. I'd rather add a 50' length to a 100' length then deal with one 250' length.

 
After reading Brian's post and how he made a great point about a "potential" fire hazzard, I understand why limiting it to a smaller run may be better.  Otherwise, in the short runs that are only 75' or 100', as he said, to make sure that the wire doesn't heat up too much and have an issue by being coiled for the remaining 150' to 175', it would have to be unwound and laid out.  Which yes, would get tedious in the smaller situations.  But again, I will have to consider that when deciding on how we set up shows.  Yes, some shows will have power 75' or 100' away.  But I've read on the other distro posts (not just here but on other sites) that others agree that the power source isn't always as close as 50' or 75'.  As they mentioned, it can be through the halls of the kitchen or some other room and by the time you run it up over the rafters of the building or along the walls and around corners to minimize having a straight run, you may easily have 150' or more to unwind.  In which case, taking out another 100' takes what, 5 minutes? 
 
Again, I appreciate the concerns about weight and having to unwrap it each time and I'll have to decide that one.  As I mentioned, if it's me who's doing it, I guess I'll only have myself to bitch at. 


By the way, "split phase" is used to mean the same as "single phase," it's referring to two legs as opposed to the one phase. "Phase" refers to the degrees of separation between the two legs-- X to Y is the same as Y to X; X to Y is different then Y to Z, which is still different then Z to X.

 
Got it.  Good info.
You asked about getting, say, 4/5 as opposed to 4/4 now-- several things here:
- Once you go to 3Ø for main feeder cable, I NEVER see it that small (#4 wire) of a cable... everything is 100A to 200A service, which requires at LEAST the #2 cable.
 
Well, at this point I am considering 2 gauge.  But again, not to be a broken record and think that it is gospel but according to the "wire calculator", running 3 phase as long as I did actually reduces the voltage drop by anywhere from .5% to 1%.  So actually, worst case scenerio would be 240 single phase and 3 phase would actually be better.  Of course this was with 50 amp service so OBVIOUSLY, 100 amp or 200 amp would be different.  But I haven't considered that yet.  Is 3 phase NEVER less than 100 amp service?  Or now let's get this question figured out, is it 100 amps total or is it 2 separate 100 amp "legs" like with the 14-50R receptacle/service where it's 50 amp service but it's actually 2 separate 50 amp "legs?"  (I'm only going off of the calculator so don't get upset at me for just using that as an example).  If it's wrong, can someone point me to the correct site to determine the accurate cable size?   
- You can connect a single phase distro to a 3Ø service
 
Which would be good for versatility correct?  (Again, thinking ahead here)
 
, but you can't connect 3Ø distros to a single phase service.  So then why limit yourself to a distro that only has 3 phase service if it ONLY can be used for 3 phase and NOT single/split phase?  Seems like a waste to me.  Of course when you're a huge production company that tours, I'm sure it's different when money isn't an issue.  I'm just thinking it's best to utilize the distro for multiple uses if it "can" be set up to. 
 
Same concept as before when discussing why a NEMA 14-50 plug with only one hot connect will cause trouble with your 240V distro-- you connect the 3Ø distro in and one of the legs will be absent!
 
Yep, since the 3 phase distro would NEED 5 wires and the 14-50R connector ONLY has 4, I can understand how this would be an issue.  Makes sense.   

Electrical sure is fun, isn't it?!? :D
 
I don't know if I would use the word "fun" to describe it.  Confusing, challenging, or overwhelming would be words I would use.  At the very least, for my conversation regarding my current situation, it IS INTERESTING. 

I hope I answered your major questions; let me know if there's something that is still confusing!
 
Well, if you read above, you'll see I got "most" of what you were saying and it makes sense.  The parts I still don't understand I have pointed out. 
 
-Ray Aberle

Man, almost 700 views in only a couple days.  This must be one hot topic.  I hope that the people reading aren't staying away because they don't want to loan their knowledge or hate my long posts.  I'm sorry about that but the information should be good for othes like me who "don't quite" understand the situation.  Better to have good power set up than not. 
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 30, 2013, 04:40:03 AM
That's not what Brian said. He said, specifically, "HIGH ampacity three-phase."

Okay, sorry about my confusion.  I didn't mean to imply that he stated that specifically but I thought by the mention of using camlocks that it meant that they "had" to be used for 3 phase.  Now that you've clerified that they (the cam locks) are used in High Amp/Load situations, then I understand now.  Thanks for clearing that up. 

In my rig, I use Motion Labs rack packs to service my amplifier racks. I have both 1Ø and 3Ø units; the 1Ø units take an L14-30 220V/30A twist lock connector and the 3Ø units take an L21-30 208V/30A twist lock connector. The service cables are 8/5 (or 10/5, depending on who is providing the cabling) multi conductor single jacket cables.

What was being referred to was running 100A/200A/400A input from a mains service to your distro; that's where you see the multiple single conductors with camlok connectors. The other advantage of going with single conductors is that they'll lay flat as opposed to a huge cable trying to hold everything together. When you're running service across large areas with cable ramps, you really want the individual conductors to be able to flow through each channel of the ramp!

That's true if you're using a ramp that has the individual cable slots allowed only.  Of course they have different walkway ramps available that would allow for use of larger diameter cable don't they?   

Ray
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 30, 2013, 09:24:49 AM

Lonnie, I'm a little dizzy from all your external processing, so forgive me for not reading everything you wrote.

RE: 250' - I'm not saying you'll never need 250', just that you won't ALWAYS need 250'.  When you don't need it, you don't want it.  Smaller chunks give you more flexibility.  This also allows your first chunk of wire (at the distro end) to be 4/4, and only your extension cables need to be bigger than that.

RE: 500' wire length - when you are calculating the resistance of the circuit, you need to consider the whole circuit - the hot wire out and the neutral wire back.  For a 250' piece of SO cord, the path length is 500', hence my calculation.  Some calculators you may find may already take this into consideration.  I didn't look in detail at your calculation or your questions about it, but keep in mind that the feeder wire you need is dependent on 3 things: The allowable voltage drop, which depends on length as well as diameter, the amount of current that can flow through the wire before the wire heats up beyond it's 75C or 90C rating or whatever, and the number of conductors making heat.  Different calculators may make different assumptions for different situations.

For pro audio you have two choices for feeder wire:  SO cable, which is multiple conductors in one jacket, and SC (or similar) single conductor cable.  SO cable is used up to about 4/4, and you can terminate a NEMA 14-50 plug on it, so a non-electrician can use the system.  SO cable must be terminated in an appropriate device - one end in a junction box, one end in a plug, etc.  It's not allowed to cut the outer jacket off and use the wires individually. 
The closeness of the wires to each other and the fact that the outer jacket is an insulator means that you have to derate the cable's current capacity for more than 2 current-carrying conductors, as there's more heat in a confined space and you run into the temperature limit with less current than if there were only 2 wires.

SC cable is used for high current distribution because it's more manageable to have a loose bundle of 4 or 5 3/4" wires than a single piece of cable the thickness of your leg - it bends more easily, and there's more airflow, allowing more current to flow through an SC bundle before the heat is a problem.

RE 3-phase - you basically cannot do a 50A 3-phase system on SO cord distro.  You won't be money ahead trying to find 4/5 wire - it won't fit in your plugs for one thing, and there's no commonly available system with which to use it.  The jump from NEMA 14-50 is to a camlok distro, and attachment of that requires a whole 'nother set of issues, not to mention understanding how 3-phase power works.

I appreciate your trying to understand this, but at some point you need to just follow the rules rather than continue to question.  Your next stop should be a pre-packaged MotionLabs, Peavey, etc. distro with a piece of 4/4 SOOW maybe 75' long and a NEMA 14-50P at the end.  For more length, you can get another piece of 2/4 SOOW (if you can fit it in your plugs), and make an extension cord.
Title: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Shane Ervin on January 30, 2013, 09:53:42 AM
Quote
  What is different at the power distro when needing to do 3 phase?  Are the components still built the same but when running into a 3 phase situation you have to change some wires around or is it a completely different junction box altogether?  I've read that the components are the same but you need to change the wiring (hence the additional wire for 3 phase vs. single phase).... <snip>

Can someone explain to me the advantages or disadvantages of 3 phase vs. 240 in simple terms?

Polyphase systems exhibit "ripple-free torque" in their transmission of power.  This is a very important attribute considering the large rotating machines (generators, motors, even hydraulic winches) involved.  In power distribution systems serving industrial and commercial areas, 3-phase is deployed for this most basic reason, historically.

From the perspective of a pro-sound provider, the question isn't so much what's the advantage for you.  Rather, it is: what's the best investment to make, knowing your gigs will take place in a mix of venues - some with 3-phase (208/120V), and some with split single phase (240V)?

For example, I chose a 3-phase RAC PAC since I know I can place all my loads on 4 breakers (leaving the remaining 2 de-energized).  Yet, I can cross rent the unit - or my entire monitor rig - to larger clients who are using 5-pin.

To interoperate with 4-pin twist, (or a 240V tie-in with tails), I use a short adapter cable (4-cond) with a 4-pin male on one end, and a 5-pin female that connects to the flanged inlet on the RAC PAC.  The "Z" light stays dark, only X & Y are lit.

A totally different approach is employed by a company nearby: they have multiple 4-pin twistlock RAC-PACs, but a 3-phase CamLok distro that powers some racks on L1/L2, some on L2/L3, some on L3/L1.  This obviates any need to re-assign loads within a rack, going from 240V venues to 208/120V shows.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Art Welter on January 30, 2013, 10:44:06 AM

Anyway, I am familiar with the voltage calculator and if I go in and put the specs in as follows:


Estimated voltage drop:  4.1%

---*(now, I put in 60 amps as a "worst" case scenerio for the type of load I "could" be pulling at a time.  Perhaps it wouldn't even be possible and the breaker at the power source would trip before it got to this point but I wanted to put that in to see what the results would be.  According to the calculations, it's still within the limits of 5% or under. 
Changing the gauge of wire to 2 gauge instead of 4 drops the voltage drop to around 2% at 50 amps and 2.4% at 60 amps so obviously that would be a benefit but it would be negligable considering the amount of money that would be spent on cable to go from 4 gauge down to 2 gauge. 
Lonnie,

You, and people with far more experience often don't realize that circuit breakers open when the average load is exceeded, short peaks as much as 10 times there rating may be sustained without blowing the breaker, but voltage drop will be severe.

Your amplifiers may have a 15 or 20 amp plug on them, but that in no way means they won't draw far more than that peak.

For example, a QSC PLX 3602 (18800 watts per channel) will draw 18 amps (average) at 1/8th power pink noise loaded at 2 ohms stereo, but 63 amps full power sine wave. It would current limit in a fraction of a second at full power and the internal breaker would pop (hopefully) before a downstream 20 amp breaker, but the point is a full power peak will draw around 60 amps from that single amplifier.

That single amplifier can easily brown out (cause excessive voltage drop) 250' of 4/4, especially considering the static lighting loads on the line already dropping voltage.
Nothing will blow except the sound on every kick drum beat.
The difference between brown out and stiff power can easily be a  6 dB loss in peak SPL.

Get 100' and 50' sections of serious wire if you need to go 250'.
That said, gigs that you need 250' of wire to reach the power source usually tend to suck so much that a 6 dB loss in PA output will usually be the least of the problems...

Art
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: RYAN LOUDMUSIC JENKINS on January 30, 2013, 11:15:56 AM
I really can't believe we have spend four pages on this thread.  We are talking about a person who is wanting to use possibly 250' of #4 or #2 cable to run a beer garden sound system.  I know of a very respectable company that is now using #4 for thier Very expensive name brand large format line array with Very expensive subs since the four channel companion amps are so efficient.  There is absolutely no reason for pieces of cable that long.  Where I work, our building codes specifically say that the generator must not be closer than 20 feet to the tents or stages.  Therefore, we have them dropped just over 20 feet away, sometimes as much as 50 feet away at the most.  I rarely use more than 50' cable lengths.

The OP doesn't need to get into this too much farther.  Buy a couple 50' pieces of 6/4 SOOW, get a Rac Pac and always have a generator setup by the provider for correct 120/240 Volt single phase operation.  Have the provider meter the voltage and then double check their work with your own meter.  Beyond that , you are not qualified based on your thread here.  Keep in mind that some people will look to the the NEC and tell you that the 6/4 SOOW is rated for 45 amps, which it is.  So don't pull more than 45 amps.  Electrical inspectors all around approve 6/4 SOOW on 50 OCPDs.  I have never met one who didn't.  You need to learn what YOUR local inspectors want. 

For what it's worth,  I don't think that you could pull 50 amps with a Beer Garden P.A.  I do lots of EDM shows and with a pretty sizable rig, way bigger than you are talking about I am only getting to around 55 amps.

If you must go into a venue that doesn't have a properly wired 50 Amp receptacle, be prepared to use extension cords.  It is really that easy and it is what we all do.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Robert Piascik on January 30, 2013, 11:59:11 AM

Man, almost 700 views in only a couple days.  This must be one hot topic.  I hope that the people reading aren't staying away because they don't want to loan their knowledge or hate my long posts.  I'm sorry about that but the information should be good for othes like me who "don't quite" understand the situation.  Better to have good power set up than not.

I'm sure I'm not the only one reading this thread but not contributing. What I like about this forum is the collective knowledge of members who know waaaaay more than I do. Sometimes reading the posts reinforces things I already knew, sometimes I learn new things. And sometimes I read the posts for the 'train wreck' aspect of guys who refuse to do things the correct way because it costs too much or who try to approach a problem from every different angle except the correct one in the name of saving money.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 31, 2013, 09:08:40 PM
Lonnie, I'm a little dizzy from all your external processing, so forgive me for not reading everything you wrote.

Tom, I'm sorry about my legthy responses.  I'm just trying to be as accurate as I can.  I know I'm not concise and never have been.  I apologize and still hope that won't stop people from contributing as I do sincerely appreciate all the help, suggestions, and knowledge I've gained so far.  I am still taking notes.

RE: 250' - I'm not saying you'll never need 250', just that you won't ALWAYS need 250'.  When you don't need it, you don't want it.  Smaller chunks give you more flexibility.  This also allows your first chunk of wire (at the distro end) to be 4/4, and only your extension cables need to be bigger than that.

I understand and I am considering a shorter length at the distro end.  But for a few reasons, I don't want it to be too short.  I do understand the hassle of dealing with unrolling a full 250' when we wouldn't need to and it would be a PITA.  I get that.  Also, the issue of "potential" heat transfer through the wires if it was coiled up in a rack and we're requesting a good chunk of power from it would be a concern.  That is noted.  Although it "may" never be an issue, I would rather err on the side of caution and not have to worry about that.  So, as someone said, it's either unroll it and spread it out for every show or use smaller chunks.  The smaller runs aren't as much of an issue but if I do split it up into say a 100' run from the distro and another 150' run for a main feeder line, I still have to deal with 2 more additional receptacles and/or plugs on that extension cable that's 150'.  Not to mention, I may or may not be able to use 4/4 SOOW cable.  I may have to jump to2/4.  I don't know and I will have to check on that. 

Again, this is where I am hopeful that some of the people's guidance on here can steer me in the right direction with the right answers.  If a 4/4 cable is safe and meets code for a 150' feeder cable from a 14-50R receptacle AND a 100' cable at either 4/4 or 6/4 from the distro is still both safe and within codes, then I would obviously be able to save a chunk of money AND WEIGHT (and size) by not having to have 2/4 feeder cable for my 150' extension.  But if 2/4 is mandatory, then that's that. 

And yes, in the end, it may come down to figuring in a few rentals of some 100' or 150' 2/4 feeder cable for a few shows since those cables aren't cheap.  $1200 to $1800 is a lot of money just to spend on cable alone so yeah, if places are willing to rent for $50 or $100, then maybe that's what I do for a few shows.  At this point, I don't know and I'll have to do some checking on rental prices.

My thing is:  if the rentals are outrageous by many places such as say $300 or $400 for a rental of a cable that big, then that's pretty hefty.  But I'll have to check.


RE: 500' wire length - when you are calculating the resistance of the circuit, you need to consider the whole circuit - the hot wire out and the neutral wire back. (I did not know this.  Thanks for the info.  But I believe the calculator I used asked for the amount of conductors for either single phase or 3 phase wiring.  They did ask for 2, 3, or 4 parallel runs for 3 phase and then a separate run or run(s) for single/split phase.  So, maybe they are allowing for that same 250' return when I put it in the calculator.  But I don't know and thank you for pointing that out.  I wasn't aware of that.)  For a 250' piece of SO cord, the path length is 500', hence my calculation.  Some calculators you may find may already take this into consideration. (yeah, I don't know and will check)  I didn't look in detail at your calculation or your questions about it, I know you probably didn't but if you did have a chance, I would appreciate checking it out.  I did try to use higher than normal figures to have a "worst case" scenerio.  But going off of what I am reading from others, 6/4 may take care of my needs for the most part.  At the very worst 4/4 would be more than sufficient and 2/4 is probably not even worth it.  But again, I don't know at this point and am still getting info.) but keep in mind that the feeder wire you need is dependent on 3 things: The allowable voltage drop (I understand and as I have said, according to the calculator site I used, the voltage drop was well within maximum limits of 5% or under), which depends on length as well as diameter, the amount of current that can flow through the wire before the wire heats up beyond it's 75C or 90C rating or whatever, and the number of conductors making heat.  Different calculators may make different assumptions for different situations.

Tom, as I have said, please refer back to the calculations I put in on the calculator.  I understand that it is not your job to do my work for me and I respect that your time is valuable so I don't "expect" you to put the calculations in for me.  However, the same things you are refering to are the same things I had to account for with that same calculator.  And I was using a longer run of 300' and even 350' and 400' just to "see" what would come up, the gauge of the cable used (2, 4, or 6 gauge), a higher amp load rating of 60 INSTEAD OF only 50 (which would be what we would be using but I used 60 just to err on the side of caution), and used a higher temperature of 90C (197F) instead of just the 75C temp "just in case" the wire was to heat up too high.   And with all of these figures being higher than the maximums, I still had voltage drops within the limits of 5% or lower.  Well, except in the case of the 6 gauge run of 350' and 400' but I'm not really considering 6 gauge at this point UNLESS it will work for sure.  Again, I would rather go bigger and be safe than not.

For pro audio you have two choices for feeder wire:  SO cable, which is multiple conductors in one jacket, and SC (or similar) single conductor cable.  SO cable is used up to about 4/4, and you can terminate a NEMA 14-50 plug on it, so a non-electrician can use the system.  SO cable must be terminated in an appropriate device - one end in a junction box, one end in a plug, etc.  It's not allowed to cut the outer jacket off and use the wires individually.  Huh, I'm finding SOOW cable up to 2/4 and 2/5.  I haven't looked for anything larger because at that point, it will be so far out of my price range that it won't even be considered an option at this point.  Maybe I'm getting wrong information about 2/4 or 2/5 cable or 4/4 or 4/5 cable.  I don't know.
 
In the situation where people use "tie ins", are you saying they CANNOT use standard SOOW cable (like a 6/4, 4/4, or 2/4 size) and "tie in" to the junction box?  Or they are not "supposed" to?  This isn't a smart butt question and is a serious one.  When I hear discussions about "tie in", I understand that cam locks are used in many cases but I also "assumed" that SOOW cable could be used as well.  Since some people discuss having multiple ends available with twist lock connectors so they can interchange for different venues with only 30 amp plugs or otherwise, I thought that they would have an interchangeable plug that would allow one for a "single strand" tie in.  In some cases, I have seen people promoting distros with no plugs or ends on them so I was "assuming" that this was so you could "tie in" to a junction box if needed.  Or is this not ok with SOOW cable? 
 
Please explain.
 
The closeness of the wires to each other and the fact that the outer jacket is an insulator means that you have to derate the cable's current capacity for more than 2 current-carrying conductors, as there's more heat in a confined space and you run into the temperature limit with less current than if there were only 2 wires.

Gotchya.  Well, I would "assume" that the calculator would take into consideration that if someone is putting in 4 gauge into the equation and putting in the amount of wires that it (the calculator) would KNOW that this would be with a SOOW cable.  But, looking at that calculator now, I am not sure since it only gives specs for 4/0 cable and NOT 4/4 cable.  Which would "possibly" mean that the calculator is indeed only figuring for each wire to be separate and NOT shielded.  It asks for conduit but does NOT ask for shielding so I would have to have that checked out.  Thanks for bringing that up. 

SC cable is used for high current distribution because it's more manageable to have a loose bundle of 4 or 5 3/4" wires than a single piece of cable the thickness of your leg - it bends more easily, and there's more airflow, allowing more current to flow through an SC bundle before the heat is a problem.

Sure, that makes sense but we're not talking about a thickness of 4" or 5".  We're talking about 2/4 SOOW cable and that is only 1 1/4" thick.  Sure, it's still heavy and a PITA and yes, "more manageable" but definately far from the thickness of our legs which is about 8".  (unless you're really skinny....not this fat boy).  Yes, airflow makes sense.

RE 3-phase - you basically cannot do a 50A 3-phase system on SO cord distro.  You won't be money ahead trying to find 4/5 wire - it won't fit in your plugs for one thing, and there's no commonly available system with which to use it.  The jump from NEMA 14-50 is to a camlok distro, and attachment of that requires a whole 'nother set of issues, not to mention understanding how 3-phase power works.

I definately agree that 3 phase is a "whole nother set of issues" and won't argue with that.  I just want to consider being prepared.  Yes, having the addional wire in that SOOW cable won't fit in any 14-50R receptacle and as such, I would have to figure out a way to leave it unavailable.  Of course I can "assume" that it can simply be left off from the connectors at each end and simply sit in the SOOW jacket couldn't it?  There wouldn't be anything wrong with that would there?  Other than it sitting there wasting space and taking up room and weight what would be the disadvantage of having it?
I appreciate your trying to understand this, but at some point you need to just follow the rules rather than continue to question.  Hold on, where am I not trying to "follow the rules?"  I'm not trying to "get away" with anything here and skip anything or not do things the right way.  I want to do things the right way.  That IS the whole point of my questions.  At the same time, I'm not going to spend $1200 to $1800 on a 2/4 cable for this project if it will not be necessary and a 4/4 cable will do just fine and save me almost half the cost.  (maybe even more depending on the overall lengths I end up using for the entire distro AND extensions)
 
Please don't tell me to stop questioning things.  That's like saying it's wrong to question things and I see nothing wrong in asking questions to get a better understanding of the situation.  I hope that wasn't your intention and if you're getting the wrong impressions from my questions, I'm sorry.  But I am sincerely trying to learn here.  I have better things to do than type novels about a subject that many may find "common knowledge."  I don't have that knowledge so I'm asking questions to learn.  And I appreciate all that's been given so far.
 
 
Your next stop should be a pre-packaged MotionLabs, Peavey, etc. distro with a piece of 4/4 SOOW maybe 75' long and a NEMA 14-50P at the end.  For more length, you can get another piece of 2/4 SOOW (if you can fit it in your plugs), and make an extension cord.

At this point, I am looking at a few options such as the Amp shop distros HOWEVER, I am concerned that those are not actually approved for UL certification or even code accepted.  Although I'm sure many have purchased them without issue, I would hate to invest even a few hundred into one of them only to find out that they are not approved for my use.  I am also considering a Furman distro as well.  Or yes, as others have mentioned, maybe even renting a few times first.  But even renting something I have to make sure that it's up to spec.  Just because I go into a place that rents distros does NOT mean that theirs are ok so, I have to kind of get the information anyway to be prepared right?
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 31, 2013, 09:14:07 PM
Polyphase systems exhibit "ripple-free torque" in their transmission of power.  This is a very important attribute considering the large rotating machines (generators, motors, even hydraulic winches) involved.  In power distribution systems serving industrial and commercial areas, 3-phase is deployed for this most basic reason, historically.

From the perspective of a pro-sound provider, the question isn't so much what's the advantage for you.  Rather, it is: what's the best investment to make, knowing your gigs will take place in a mix of venues - some with 3-phase (208/120V), and some with split single phase (240V)?

For example, I chose a 3-phase RAC PAC since I know I can place all my loads on 4 breakers (leaving the remaining 2 de-energized).  Yet, I can cross rent the unit - or my entire monitor rig - to larger clients who are using 5-pin.

To interoperate with 4-pin twist, (or a 240V tie-in with tails), I use a short adapter cable (4-cond) with a 4-pin male on one end, and a 5-pin female that connects to the flanged inlet on the RAC PAC.  The "Z" light stays dark, only X & Y are lit.

A totally different approach is employed by a company nearby: they have multiple 4-pin twistlock RAC-PACs, but a 3-phase CamLok distro that powers some racks on L1/L2, some on L2/L3, some on L3/L1.  This obviates any need to re-assign loads within a rack, going from 240V venues to 208/120V shows.

Shane, thanks for the input.  I really appreciate it.  I think 3 phase is over my head at this point but just wanted to know if it was something to consider for future use.  And your mention about "some" venues that may have it (and only have that) and "some" that will have the 240 service are why I want to consider it.  I don't want to be screwed at a place.  But again, site surveys will be done so this "shouldn't" be an issue.  Also, your mention of renting a distro to someone that needs it for dual purpose use is also a reason why I am considering it.  I would like to have that option as well.  Even if it's only $50 a show or $100 for a weekend, I would rather my equipment be out there making money and getting rented than not and just sitting in the warehouse or trailer or truck.  By limiting myself to only a 240 distro without the additional wire for 3 phase, I may limit the ability to have it be rented/used in "some" cases. 

Just trying to think ahead is all. 
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 31, 2013, 09:21:05 PM
Lonnie,

You, and people with far more experience often don't realize that circuit breakers open when the average load is exceeded, short peaks as much as 10 times there rating may be sustained without blowing the breaker, but voltage drop will be severe.
 
Okay.


Your amplifiers may have a 15 or 20 amp plug on them, but that in no way means they won't draw far more than that peak.
 
I know this.  They can be 50, 60, or even 80 amps in some cases.  But those are short "bursts" and from what I understand, won't trip a breaker UNLESS it's too much or too frequent.  Anyway, we could talk all night about that but I understand that an amp will pull more than it's stated 7, 10, 12, or 15 amp 1/8 power rating. 

For example, a QSC PLX 3602 (18800 watts per channel) will draw 18 amps (average) at 1/8th power pink noise loaded at 2 ohms stereo, but 63 amps full power sine wave. It would current limit in a fraction of a second at full power and the internal breaker would pop (hopefully) before a downstream 20 amp breaker, but the point is a full power peak will draw around 60 amps from that single amplifier.
 
Not to be a stickler but you've got a typo there.  It's actually "1800 watts per channel" and that's into a 2 ohm load per channel.  Yeah, that amp is pulling some serious juice.  Yikes.  But, that's what it takes to have good sound.  Good power.


That single amplifier can easily brown out (cause excessive voltage drop) 250' of 4/4, especially considering the static lighting loads on the line already dropping voltage.
 
True, but I'm sure you're not running that amp (or others you may have) at full load all the time are you?  If you were, you would be tripping breakers left and right.  And yes, other loads (not just lights) will have an effect on the "overall" load.

Nothing will blow except the sound on every kick drum beat.
The difference between brown out and stiff power can easily be a  6 dB loss in peak SPL.

Yeah, sucks but that's why we have to be knowledgeable and careful.

Get 100' and 50' sections of serious wire if you need to go 250'.
That said, gigs that you need 250' of wire to reach the power source usually tend to suck so much that a 6 dB loss in PA output will usually be the least of the problems...

That's true. 

Art

Thanks for the info Art.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 31, 2013, 09:38:18 PM
I really can't believe we have spend four pages on this thread.  We are talking about a person who is wanting to use possibly 250' of #4 or #2 cable to run a beer garden sound system.

Well, a "beer garden sound system" could be small in some people's minds.  We all may have a different idea of what "small" or "large" is.  (insert stupid penis joke here)...
 
Anyway, if we're talking about 3000 or 4000 watts and a few LED lights, then you can probably get away with some heavy gauge extension cords if there are two separate 20 amp power sources nearby.  But in a "beer garden" setting, having power close by is not always the case.  Or, if it is, it may not be on separate circuits/legs.
 
But I'm not referring to these (in my mind) "smaller" events where only 1 or 2 separate 20 amp outlets are needed.  I'm referring to something larger where we will have a good amount of sound and lighting.  So, we will need more than an outlet or two.
I know of a very respectable company that is now using #4 for thier Very expensive name brand large format line array with Very expensive subs since the four channel companion amps are so efficient.  There is absolutely no reason for pieces of cable that long.  Where I work, our building codes specifically say that the generator must not be closer than 20 feet to the tents or stages.  Therefore, we have them dropped just over 20 feet away, sometimes as much as 50 feet away at the most.  I rarely use more than 50' cable lengths.

Well, I understand that you may not use more than 50' in "most" cases but I'm considering situations where in a bar they do indeed have these stupid 14-50R receptacles 100' away (or more) and we do have to go through the kitchen and etc.  (yes, that sucks but that's life).  Or, in a basketball gym or large arena where we're doing a concert or just a DJ sound system and line of site is at least 75' to 100' from the stage area (where the amp racks would be) and the power source (which is down the hall, around a corner, and in some stupid electricians closet a mile away.  In which case, I don't want to be running cable stright across the floor for people to trip on.  Whether it's a bar, gym, or an outdoor event, I want to have the cable in THE MOST inconspicuous AND SAFE place possible. 

The OP doesn't need to get into this too much farther.  Buy a couple 50' pieces of 6/4 SOOW, get a Rac Pac and always have a generator setup by the provider for correct 120/240 Volt single phase operation.
 
It's easy to say "always have a generator setup by the provider" but you realize that this adds cost to the event right?  Also, if "I" am the provider (the host, promotor/marketer, coordinator, agent, pee-on, setup crew, and the whole 9 yards), then I have to be the one to consider this aspect too since again, it eats into costs.  I know we can rent generators but they aren't cheap either.
 
Have the provider meter the voltage and then double check their work with your own meter. (see above) Beyond that , you are not qualified based on your thread here.  (I know this.  That's why I'm trying to keep it as simple as plugging in a 14-50R receptacle / plug in.  I don't want to be worrying about cam locks or "tying in.")  Keep in mind that some people will look to the the NEC and tell you that the 6/4 SOOW is rated for 45 amps, which it is.  So don't pull more than 45 amps.  Electrical inspectors all around approve 6/4 SOOW on 50 OCPDs.  I have never met one who didn't.  You need to learn what YOUR local inspectors want.
 
Correct, and I am.  However, I can't know what every inspector wants to see but I am sure there is a fairly "standard" practice that people can shed some experience/wisdom on.  I get that the final say WILL ALWAYS BE the inspector within that state, city, community, village, region or whatever.  But I am hopeful that putting together a distro that will work with 240 volt service off of a 14-50R receptacle for "most" places won't be that hard.  Yes, I know it's 4 pages but I'm hopeful it's not just good info for me but others as well. 
 
For what it's worth,  I don't think that you could pull 50 amps with a Beer Garden P.A.  I do lots of EDM (sorry, I'm not familiar with what "EDM" stands for) shows and with a pretty sizable rig, way bigger than you are talking about I am only getting to around 55 amps.  (are you talking 55 amps total for both legs or 55 amps per leg?  Know knowing what I know (learning from you folks and other boards), it is obvious that you couldn't pull 55 amps per leg but just asking. 

If you must go into a venue that doesn't have a properly wired 50 Amp receptacle, be prepared to use extension cords.  It is really that easy and it is what we all do.  Yeah, I know and I have plenty of extension cords.  It just sucks having to do that.  Obviously, that brings up a great point that EVEN THOUGH I could have this great distro and wire my amps to work with it, I may have to change things around in certain situations.  In which case yes, I may have to go back to using some separate circuits.  Ugg....

 
Thanks for the info. 
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on January 31, 2013, 09:44:54 PM
I'm sure I'm not the only one reading this thread but not contributing. What I like about this forum is the collective knowledge of members who know waaaaay more than I do. Sometimes reading the posts reinforces things I already knew, sometimes I learn new things. And sometimes I read the posts for the 'train wreck' aspect of guys who refuse to do things the correct way because it costs too much or who try to approach a problem from every different angle except the correct one in the name of saving money.

Robert,
I don't know if you're referring to me as a "train wreck" or not so at this point, I can only speculate about your comments.  I am hopeful that you're not intending that to be the case because I am not wanting my situation to end up like that.  THAT IS why I am asking so many questions and looking at this from ALL angles. 

It's similar to buying a car as you know.  We can all get a vehicle that gets us from point A to B but we all know that some of them will be cheaper, and some will be more.  And with each different model will come advantages and disadvantages.  But I'm not trying to "skimp" on anything just for the sake of being "cheap" by any means.  I just don't want to invest $2000 or $3000 if I could get what I need for $1000 or even $500.  I'm just being thrifty here and that's all. 

The comments about using a standard 10/3 UL listed cable are only because of my curiosity.  It in NO WAY means that that I would use it UNLESS it was acceptable.  I could assume that there is a reason why it wasn't used but I didn't know what it was.  Now I do since I've learned that.  But that's just one particular thing out of the many I've learned in the last week since posting my questions in different areas. 

And it's NOT just about power distros.  It's about amps, speakers, placement, cable size, harmonics, setup, logisitics, and so on.  Even though I've been at this for a while now, I've learned so much in the last 6 months that I feel like I'm starting over and I wish I would have known what I do now years ago.  But don't we all? 

I guess I'm "livin' and learnin'."
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 31, 2013, 10:31:46 PM
Lonnie, I appreciate you trying to understand power distribution.  That being said, you're spinning on things that are just wrong, and you need to accept the facts:

- There is no way to be ahead using 5-conductor wire for your use.  It won't be reusable in some hypothetical future 3-phase world.  If you ever go 3-phase, you'll be into SC single-wire camloks.  5-phase wire won't fit in your plugs, and you can't just cut one of the wires off, since the jacket has to fit inside the plugs.

- 4/4 SOOW is 1.3" in diameter.  2/4 SOOW is 1.5" in diameter and weighs 1.7lbs/ft.

- I have no idea what calculator you're using.  Voltage drop can be calculated with Ohm's law.  As Art said, the nominal load that the NEC roles are based on doesn't take into account the instantaneous current draw of big power amps, which can be several times the nominal load.  You can choose to disregard this for wire sizing and you'll be "safe" from starting a fire and legal, but you'll pay the voltage drop penalty of the entire instantaneous load, not just the constant load, so the smaller and/or longer your feeder is, the mushier your power will be.  This has a direct impact on your system's output.

A calculation example:  100A on 100' of 6/4 has a voltage drop of 8 volts.  Assuming you start with 120, that leaves 112 volts left.  Up that to your 250' and your voltage drop is 20 volts.  100 volt brownouts are low enough to reboot digital mixers, and generally goof up everything, and that's assuming you actually have 120 volts to start with.

Moving that same wire to 250' of 4/4 and now your voltage drop is 12.5 volts.  That's still marginal, but a lot better than 6/4.

My example of 75' of 4/4 plus another 150 of 2/4 leaves your voltage drop at 7 volts, which is likely acceptable.


There are a lot of nuances here, and there is some wiggle room.  I happen to disagree with Ryan about the use of 6/4 cable.  I think even Ryan would agree that 6/4 cable at 250' isn't a good idea.

I stand by my recommendation - 75' of 4/4SOOW cable with a NEMA 14-50 plug.  Optionally add a piece of up to 150' of 2/4 SOOW cable with a NEMA 14-50 plug on one end and receptacle on the other.  If it gets much longer than this, you're better off with a generator (a good one).
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: RYAN LOUDMUSIC JENKINS on January 31, 2013, 11:10:44 PM
Lonnie,  EDM stands for Electronic Dance Music.  Pretty much regarded as extreme duty cycle on your equipment.  When I say 55 amps,  that is single phase 120/240.  Therefore approximately 55 amps measured per leg.  That is with 16 2X18" subs, 8 3-way tops, Monitors, etc.  All turned up to a rediculous volume for hours on end.  I run each amp rack off of it's own circuit with 6/4 cable.  This rig uses four separate runs out of my distro to the amp racks.  I measure the current on the feeder coming into the distro.


With regards to TJ (Tom) Cornish and talking about running long 6/4 cables,  I have had to multiple runs as far as 300' before.  It isn't fun at the end of the night rolling it all back up.  I really don't recommend running more than 100' of 6/4 if you can avoid it as there will potentially be a lot more risk of voltage drop.  Generally if we are more than 100' from the power source we want the generator provider to run 2/0 or 4/0 5-Wire for us.  I do own some 5-Wire banded #2 cable and use it when needed.  I also have some 2/4 SOOW with Cam Locks and it is a complete bitch to work with.  For only being rated at 80 amps it really isn't worth owning or using.  I would rather just use 5-Wire banded (#2) and have 190 Amps rating.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: TJ (Tom) Cornish on January 31, 2013, 11:15:11 PM
Lonnie,  EDM stands for Electronic Dance Music.  Pretty much regarded as extreme duty cycle on your equipment.  When I say 55 amps,  that is single phase 120/240.  Therefore approximately 55 amps measured per leg.  That is with 16 2X18" subs, 8 3-way tops, Monitors, etc.  All turned up to a rediculous volume for hours on end.  I run each amp rack off of it's own circuit with 6/4 cable.  This rig uses four separate runs out of my distro to the amp racks.  I measure the current on the feeder coming into the distro.


With regards to TJ (Tom) Cornish and talking about running long 6/4 cables,  I have had to multiple runs as far as 300' before.  It isn't fun at the end of the night rolling it all back up.  I really don't recommend running more than 100' of 6/4 if you can avoid it as there will potentially be a lot more risk of voltage drop.  Generally if we are more than 100' from the power source we want the generator provider to run 2/0 or 4/0 5-Wire for us.  I do own some 5-Wire banded #2 cable and use it when needed.  I also have some 2/4 SOOW with Cam Locks and it is a complete bitch to work with.  For only being rated at 80 amps it really isn't worth owning or using.  I would rather just use 5-Wire banded (#2) and have 190 Amps rating.
Ryan - just curious how you're metering this - i.e. what's the response time of your meter?  I know even my Fluke 289 is a little slow and misses the tops of the peaks sometimes.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: RYAN LOUDMUSIC JENKINS on January 31, 2013, 11:41:07 PM
Ryan - just curious how you're metering this - i.e. what's the response time of your meter?  I know even my Fluke 289 is a little slow and misses the tops of the peaks sometimes.

I have several clamp multimeters from cheap $10 units to $50 units of various home depot varieties, none of which are true RMS.  They all measure approximately the same.  I could not tell you the response times, I have no idea what they or if a spec was even in the monuals for that. 

I started a thread about currect draw about a year ago after being surprized at how low the current draw was.  After starting that thread and wanting to know if my meters were accurate or not I borrowed a friends very over priced but fancy Fluke unit and it showed no appreciable difference in current draw.   

Read here
http://forums.prosoundweb.com/index.php/topic,136370.msg1273904.html#msg1273904

I think we all expect our gear to pull way more current than it actually does.  Modern amplifiers are very efficient and sip electricity rather than gulping it.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on February 01, 2013, 01:57:17 AM
Lonnie, I appreciate you trying to understand power distribution.  That being said, you're spinning on things that are just wrong, and you need to accept the facts:
 
Tom, I understand when I first posed the many questions, there was a lot I had no idea about.  But since then, many people have been kind enough to inform me of some things.  (you're on of them).  And in that time, I've come to understand a lot of things.  However, I'm not claiming to know it all by any strethc of the imagination. 

But if I am indeed wrong about something, can you please kindly point out where, why or how?  To simply say that I am "spinning on things that are just wrong" is a fairly blunt statement that (to me) implies that I am wrong about many things.  Maybe you only mean one thing.  Or maybe it's two or three.  But whatever it is, what is it?  I thought I had a pretty good understanding of things at this point.  (for the most part).  However, if people are informing me that certain gauge wire should be acceptable and certain length runs should also be and that the distro can be built to accept either 240 volt single phase or 208 volt 3 phase service (and also 120 at the same time obviously) then what information is incorrect? 

I'm not saying that to be sarcastic but explain exactly how I'm "spinning my wheels" here.

- There is no way to be ahead using 5-conductor wire for your use.  It won't be reusable in some hypothetical future 3-phase world.  (okay, I'm reading and trying to understand) If you ever go 3-phase, you'll be into SC single-wire camloks.  (well, if camloks are mandatory then yes, I'm not wanting to go that route at this point)  5-phase wire won't fit in your plugs, and you can't just cut one of the wires off, since the jacket has to fit inside the plugs.  Okay

- 4/4 SOOW is 1.3" in diameter.  2/4 SOOW is 1.5" in diameter and weighs 1.7lbs/ft.
 
I understand that different manufacturers "may" be a little different in their overall dimensions for wire thickness and overall jacket size but here is where I got my information.  If you scroll all the way to the bottom, you'll see the sizes for 2/4 and 4/4. 
 
According to their sizes, 2/4 has an outside diameter thickness of 1.170 inches.  1.5 would be 1 1/2 inches and 1.250 would be 1 1/4" so their figure is just under 1 1/4 inches according to their specs. 
 
4/4 is 1.010 on their site so it is essentially 1" around.
 
I'm not pointing this out to argue in any way at all.  That would gain me nothing.  I'm simply stating that this is where I got one figure.  Of course many different companies could have different figures.  Also, I don't know if this is for 50', 100' or 200' or 400' increments.  Perhaps for long runs the outside diameter is more.  But the specs don't say whether it is for a certain distance or not so I don't know.
 
Here is the link:   http://www.awcwire.com/ProductSpec.aspx?id=SOOW-Cable-8to2-AWG (http://www.awcwire.com/ProductSpec.aspx?id=SOOW-Cable-8to2-AWG)
 

- I have no idea what calculator you're using.
I'm sure it's the same one that a lot of people use.  I saw it quite a while ago but it was also the same one that has been recommended by a few different people on different forums and groups.  It's this one here:
http://www.nooutage.com/vdrop.htm (http://www.nooutage.com/vdrop.htm)
 
Voltage drop can be calculated with Ohm's law.  As Art said, the nominal load that the NEC roles are based on doesn't take into account the instantaneous current draw of big power amps, which can be several times the nominal load.  (I understand this and also know that I have to take this into consideration.  That is why I am trying to find out what the "safe" area is for running equipment off of a distro.  If it is 40 amps per side, then that's that.  If it's 49 amps per side, then that's that.  If it's 49 1/2 amps per side and once you hit 50 amps per side you're tripping breakers, then that's that too.  But I understand that it's 50 amps per side *HOWEVER*, there are these "instantaneous bursts" that we have to consider.  Which means we can't be pushing our stuff to full blast as we may "want" to.  Again, this is knowledge and/or experience.  Or both.  I'm sure there's some great math involved too but the bottom line is, know what the limits are and do NOT go above them. 
 
That's what I'm trying to understand to be safe and within codes.
 
You can choose to disregard this for wire sizing (not trying to do that at all.  I want to be safe) and you'll be "safe" from starting a fire and legal, but you'll pay the voltage drop penalty of the entire instantaneous load, not just the constant load, so the smaller and/or longer your feeder is, the mushier your power will be.
 
Again, I understand which is why I am trying to get as accurate of info as I can.  Thanks.
 
This has a direct impact on your system's output.  (very true)

A calculation example:  100A on 100' of 6/4 has a voltage drop of 8 volts.  Assuming you start with 120, that leaves 112 volts left.  Up that to your 250' and your voltage drop is 20 volts.  100 volt brownouts are low enough to reboot digital mixers, and generally goof up everything, and that's assuming you actually have 120 volts to start with.  (yes, and sucking that much power well....sucks.  Literally and figuratively.  No, I don't want to be using too much power to get the performance I want AND risk it being unsafe or not up to code.  I understand that more seasoned professionals with a lot more experience than me can determine how much of a load they will be pulling based on meters, test equipment, mult-meters, and probably a lot of experience.  I'm not trying to get to that point and want to do things as best I can.  And within budget too.)

Moving that same wire to 250' of 4/4 and now your voltage drop is 12.5 volts.  That's still marginal, but a lot better than 6/4.  (agreed it's a lot.  I'm only going off of the voltage calculator at this point.  I haven't went and done any other math for things yet.  If there is a better way to figure, I would rather do that so I will either have to look back through the many pages of notes or go online and do some more research.  That's why I'm here.)

My example of 75' of 4/4 plus another 150 of 2/4 leaves your voltage drop at 7 volts, which is likely acceptable.  (And that may well be the best option.  I don't know at this point.  Still trying to get info.)


There are a lot of nuances here, and there is some wiggle room.  I happen to disagree with Ryan about the use of 6/4 cable.  I think even Ryan would agree that 6/4 cable at 250' isn't a good idea.
 
Well, I'll assume that Ryan knows what he's doing in "his" situations and maybe under "his" conditions, 6/4 is acceptable.  Or maybe he is giving a recommendation based on facts and figures from previous engineering and so forth.  I am hopeful it is from research and the engineering but I don't know.  Going off of the simple calculator I used, although 6/4 "probably" would be sufficient and safe AND still pass codes, I can't imagine 6/4 being good for a 250' run according to the small amount of research I've done.  But if I'm incorrect, please let me know.  I'm all for saving money if it is acceptable to do so. 
 
And we all know that 6/4 cable compared to 4/4 cable would be around a 30% difference or more.  That's HUGE when we're talking about 250' or 300'.


I stand by my recommendation - 75' of 4/4SOOW cable with a NEMA 14-50 plug.  Optionally add a piece of up to 150' of 2/4 SOOW cable with a NEMA 14-50 plug on one end and receptacle on the other.  If it gets much longer than this, you're better off with a generator (a good one).  (you may be right.  More than likely, I will end up with either 75' or 100' off the distro and a 150' extension (main feeder) cable.  But I'm concerned about how that will be accepted for codes by having that additional "link" in the chain with the added outlets in the middle. 

Again, thanks for the input.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on February 01, 2013, 02:08:31 AM
Lonnie,  EDM stands for Electronic Dance Music. 
 
Ahh...gotchya.  I guess I'm used to the terms:  house, trance, techno, dubstep, and so on.  Although I can do it, that type of music is definately NOT my background and I rarely every get requests for it at my shows.  Of course, we have to be ready for those songs when doing a larger dance show though.
 
Pretty much regarded as extreme duty cycle on your equipment.  When I say 55 amps,  that is single phase 120/240.  Therefore approximately 55 amps measured per leg.  That is with 16 2X18" subs, 8 3-way tops, Monitors, etc.  All turned up to a rediculous volume for hours on end.  I run each amp rack off of it's own circuit with 6/4 cable.  This rig uses four separate runs out of my distro to the amp racks.  I measure the current on the feeder coming into the distro.

And may I ask what size wire you're using for your distro to branch out 4 ways to your amp racks?  Obviously it's not 6/4 cable right?  Nice setup btw.  I couldn't imagine listening to that for hours on end though.  I'll take my ears thanks.

With regards to TJ (Tom) Cornish and talking about running long 6/4 cables,  I have had to multiple runs as far as 300' before.  It isn't fun at the end of the night rolling it all back up.  I really don't recommend running more than 100' of 6/4 if you can avoid it as there will potentially be a lot more risk of voltage drop.  (that seems to be the consensus from here and other forums/groups so yeah...that is a huge concern and why I'm wanting to not "skimp" on the cable.)  Generally if we are more than 100' from the power source we want the generator provider to run 2/0 or 4/0 5-Wire for us.  (okay.  So let me ask you a question even though I know it will vary based on size and location and so on but.....what size generator do you typically get in these situations and what do they "typically" charge you to drop them off and set them up for you for a day rate or weekend rate?  Considering that they don't allow you to come get them and set them up yourself and drop the cables yourself (as you said they do it), what do they "typically" rent for in your area?  I do own some 5-Wire banded #2 cable and use it when needed.  I also have some 2/4 SOOW with Cam Locks and it is a complete bitch to work with.  For only being rated at 80 amps it really isn't worth owning or using.  I would rather just use 5-Wire banded (#2) and have 190 Amps rating.  And now we're talking back into the future of things with preparation for the future.  Yeah, I am not worried about anything "that" big yet.  But I agree, in the end, having 2/4 cable may just not be worth it for the amount of shows I'll be doing for a little while.  Again, I have to sit down and figure that out.

Thanks for the info.
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: Lonnie Eldridge on February 01, 2013, 02:36:10 AM
I have several clamp multimeters from cheap $10 units to $50 units of various home depot varieties, none of which are true RMS.  They all measure approximately the same.  I could not tell you the response times, I have no idea what they or if a spec was even in the monuals for that. 

I started a thread about currect draw about a year ago after being surprized at how low the current draw was.  After starting that thread and wanting to know if my meters were accurate or not I borrowed a friends very over priced but fancy Fluke unit and it showed no appreciable difference in current draw.   

Read here
http://forums.prosoundweb.com/index.php/topic,136370.msg1273904.html#msg1273904

I think we all expect our gear to pull way more current than it actually does.  Modern amplifiers are very efficient and sip electricity rather than gulping it.

Great info.  I read it all.  Very interesting and eye opening.  And somewhat refreshing and definately helps put things in perspective for a lot of things.

What meter are you going to be using or do you use now?  You said you use a clamp on style right?  Do you just leave it on or just use it when you want to take some readings?
Title: Re: Power distros for entertainment like bands & concerts or stage & theatre shows
Post by: RYAN LOUDMUSIC JENKINS on February 01, 2013, 08:55:54 AM
And may I ask what size wire you're using for your distro to branch out 4 ways to your amp racks?  Obviously it's not 6/4 cable right?

Yes, my amp rack each get 6/4 cable run to them.  Typical setup would be Generator with #2 5-Wire Banded on Cam Locks to my Distro.  From my distro to Amp Racks with 6/4.  I do a ton of work with generators so I chose to go with 50 amp connectors on my Rack Packs so I can plug right into the 50 amp courtesy plugs on generators.  Much faster and easier if I only need a couple runs of 6/4.  No need to bring out the distro.



let me ask you a question even though I know it will vary based on size and location and so on but.....what size generator do you typically get in these situations and what do they "typically" charge you to drop them off and set them up for you for a day rate or weekend rate?  Considering that they don't allow you to come get them and set them up yourself and drop the cables yourself (as you said they do it), what do they "typically" rent for in your area?

I use anything from 25kVA to 125kVA depending on the application,

Where I work, you typically need to get a generator permit and have them inspected so I let the event coordinators/promoters deal with it these days.  Many jurisdictions require two ground rods 8' deep on 45 degree angles, I'll let the generator supplier pound that into the ground and remove at the end of the show!  Generators can be had for as little as $125 + Fuel + delivery and pickup for a typical 8 hour day or they can cost upwards of a couple grand depending on what is needed.