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Author Topic: Power distros for entertainment like bands & concerts or stage & theatre shows  (Read 44142 times)

Lonnie Eldridge

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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.
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Tim McCulloch

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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."
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TJ (Tom) Cornish

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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.
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Jerome Malsack

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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. 

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TJ (Tom) Cornish

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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.
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roblavender

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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
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g'bye, Dick Rees

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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".

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Tim McCulloch

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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.
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Greg_Cameron

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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.
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Lonnie Eldridge

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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/distroI'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.   :)
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