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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Jeffery Foster on September 17, 2014, 01:26:19 pm

Title: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Jeffery Foster on September 17, 2014, 01:26:19 pm
Let's say I arrive at a new venue five hours from home.  Since I did a fastidious advance of the venue, I know that they have a single-phase 100 amp cam lock tie in.  That's great, I stroll in with my single-phase distro with cam lock tails, but what's this? Five cams at the tie in? And one of them is BLUE? And it says 200A on it?! The owner says "My bad, I gave you incorrect information."  Ah nuts.

So, would I be able to connect only my two hot legs, the neutral, and the ground to the power? And if so, what kind of voltage/amperage should I expect?

Thank you for anyone who can provide insight to this very potential situation!
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on September 17, 2014, 02:20:58 pm
Let's say I arrive at a new venue five hours from home.  Since I did a fastidious advance of the venue, I know that they have a single-phase 100 amp cam lock tie in.  That's great, I stroll in with my single-phase distro with cam lock tails, but what's this? Five cams at the tie in? And one of them is BLUE? And it says 200A on it?! The owner says "My bad, I gave you incorrect information."  Ah nuts.

So, would I be able to connect only my two hot legs, the neutral, and the ground to the power? And if so, what kind of voltage/amperage should I expect?

Thank you for anyone who can provide insight to this very potential situation!
It is safe to ignore the third phase, though the unused cam must be covered or taped to prevent a shock hazard. 

The question of it being safe to plug a 100A distro into a 200A company switch depends on the circumstances.  If your feeder cable can handle 200A and your distro has a 100A main breaker, then yes.  If your feeder is only rated for 100A or your distro doesn't have a main breaker, technically no, though it is commonly done.

The general rule of thumb is that the role of an OCPD is to protect the downstream wiring.  If your OCPD is 200A, in the letter of the law, all the wiring between this 200A OCPD and the next step down in distribution must be rated at 200A.  If not, this wire could potentially overheat, and the 200A OCPD will not prevent an unsafe condition.

Depending on the construction of your distro, if it doesn't have a main breaker, that makes it even more of a risk to plug in to an oversize supply, as now you could potentially overload your distro's internal distribution busses. 

If your distro has an appropriate main breaker, say 100A, then the distro itself is protected, and to a large degree your feeder is as well.  Though technically it is a code violation to plug a 100A main breaker distro with 100A rated tails into a 200A company switch, it is commonly done and reasonably safe.  The technically correct solution would be to carry a set of 200A-capable feeder either all the way to your distro, or a short distance to a portable 100A breaker, then use your 100A feeder to go the rest of the way to the distro.

As to power capacity, if you have what is commonly called a 100A distro - a 100A two pole breaker, then you will have two 100A legs available for use, no matter whether you are supplying it from a single phase or 3-phase service.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Jeffery Foster on September 17, 2014, 02:26:42 pm
Outstanding Tom, I appreciate the detailed answer.

Not that I would ever run into that situation....
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Jonathan Johnson on September 17, 2014, 03:59:45 pm
As to power capacity, if you have what is commonly called a 100A distro - a 100A two pole breaker, then you will have two 100A legs available for use, no matter whether you are supplying it from a single phase or 3-phase service.

Be aware that if you are tying into a 3-phase Y service, you will NOT have 240V split-phase service available in your distro. You will have 120V single phase between each hot and neutral, and 208V between the two hots. (The neutral is tapped where the three transformer windings meet.)

If you are tying into 3-phase high-leg Delta service, the neutral is typically center-tapped on one winding of the transformer, so you will have 120V single phase between each hot and neutral and 240V single-phase between the two hots (AKA 240V split-phase). The high leg is opposite the neutral -- that is, the high leg is where the two other windings on the transformer meet. You will have 208V between either hot leg and the high leg.

Even though the 208V is using two 120V phases that are 120 degrees relative to each other, the waveforms add to produce a sine wave at 208V RMS so it appears as a single phase to the equipment. Equipment with universal power supplies that spec a single-phase range from 100V-250V (or so) will operate fine on 208V service.

Three phase service is really only useful for motors and other loads with a matched triplet of coils or elements. Pretty much all lighting and sound equipment is single phase, though distributing the single-phase loads among the three phases is done for balance. With switching power supplies and loads not power-factor corrected, there can be issues with overloading the neutral of three-phase service if it is undersized, as distorted current waveforms can be additive rather than cancelling.

Probably too much information for what you need. Always meter the service prior to connection. Never assume anything!
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on September 17, 2014, 04:45:33 pm

The question of it being safe to plug a 100A distro into a 200A company switch depends on the circumstances.  If your feeder cable can handle 200A and your distro has a 100A main breaker, then yes.  If your feeder is only rated for 100A or your distro doesn't have a main breaker, technically no, though it is commonly done.

The general rule of thumb is that the role of an OCPD is to protect the downstream wiring.  If your OCPD is 200A, in the letter of the law, all the wiring between this 200A OCPD and the next step down in distribution must be rated at 200A.  If not, this wire could potentially overheat, and the 200A OCPD will not prevent an unsafe condition.

Code allows undersize wired after a OPCD if it runs to a single breaker/set of fuses that limits current to the wire ampacity-under the tap rules within certain limitations.  Though, I am guessing that since portable cord-usually on the ground-is susceptible to damage causing a short that it is probably not allowed in that case? (even if allowed, likely not a good idea!)
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on September 17, 2014, 04:55:40 pm
Code allows undersize wired after a OPCD if it runs to a single breaker/set of fuses that limits current to the wire ampacity-under the tap rules within certain limitations.  Though, I am guessing that since portable cord-usually on the ground-is susceptible to damage causing a short that it is probably not allowed in that case? (even if allowed, likely not a good idea!)
Don't quote me on this, but I believe that is only allowed for a length of something like 10'.  I don't have a code reference off the top of my head.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Jay Barracato on September 17, 2014, 08:33:13 pm
I was remembering the same thing with the same short length of the feeder

Sent from my DROID RAZR HD using Tapatalk

Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 21, 2016, 04:21:47 pm
Not sure if this topic is still open or being monitored by folks here, but have a question. I am faced with this exact situation in a couple of months. I have a suitcase style single phase distro that has a mix of single 15A and 20A breakers and outlets. The venue I am setting up in has 3 phase power, so my plan is to tie in my black and red, and cap or tape the blue leg. The good news in my case (I think) is that my feeder is #2 which should be good for 195A, which matches nicely with their 100A panel (200A total).

Here is my question, the venue has 2 CAM panels, one is rated at 100A the other at 400A. I think I read somewhere that this means each leg has that amperage rating, and not the entire feed, is this correct ?? So in the case of the 100A panel (3-phase), if I only use 2 legs I get 2 X 100A, correct ??

Even though I won't be pulling more than 100A total in gear, I am thinking that since my feeder is #2, and I don't have a main breaker in my distro, it is probably a better (not good) idea to cable into the 100A panel and not the 400A one, but again, I won't be pulling more than 100A in gear, so my feeder should be fine.

Thanks
Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 21, 2016, 04:48:08 pm
Not sure if this topic is still open or being monitored by folks here, but have a question. I am faced with this exact situation in a couple of months. I have a suitcase style single phase distro that has a mix of single 15A and 20A breakers and outlets. The venue I am setting up in has 3 phase power, so my plan is to tie in my black and red, and cap or tape the blue leg. The good news in my case (I think) is that my feeder is #2 which should be good for 195A, which matches nicely with their 100A panel (200A total).

Here is my question, the venue has 2 CAM panels, one is rated at 100A the other at 400A. I think I read somewhere that this means each leg has that amperage rating, and not the entire feed, is this correct ?? So in the case of the 100A panel (3-phase), if I only use 2 legs I get 2 X 100A, correct ??

Even though I won't be pulling more than 100A total in gear, I am thinking that since my feeder is #2, and I don't have a main breaker in my distro, it is probably a better (not good) idea to cable into the 100A panel and not the 400A one, but again, I won't be pulling more than 100A in gear, so my feeder should be fine.

Thanks
Neil
You really should have a main breaker in your distro.

The upstream breaker is designed to protect the downstream wiring.  In your specific case, if you have #2 SC cable, you need to have an upstream breaker at <195 amps.  If you have some other kind of #2 cable such as multi-conductor SOOW cable, this number is different and almost certainly significantly lower than 195 amps, and there may be other problems with your setup; e.g. it is not allowable to break out SOOW cable into camlok connectors.

If you are drawing power from a 100A main breaker, you will have 2 legs of up to 100A/120V available each, or 200A/120v total.  If you are using 208/240v loads, you will have 208/240v/100A available, or whatever combination is in between.

The 400A breaker is definitely not acceptable for your situation.  Even if you aren't intentionally pulling 400A, one or more faults could exceed the rating of some component(s) in your system and you would be in big trouble.

Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 21, 2016, 05:30:19 pm
Thanks Tom for the info !!! Yes I am using SC cable (#2) which is good for 190A. I hear you on the main breaker thing, but most of the companies who make custom distro panels usually don't have or sell a main breaker for the distro, including my distro, not really sure why. I guess they don't want to limit the distro as it all depends on which wire and application the distro will be applied.

In my case, I have 8 X 15A mini breakers and 8 X 20A SqD breakers all tied to Edison outlets on panels, and underneath the panels, all wiring from all breakers tie straight into the CAMS. My suitcase style case doesn't even have room for another panel to house a main breaker.

But I hear you loud and clear, the main breaker protects the total capacity of the feeder, in my case #2 / 190A, when tying into a higher panel like a 3-phase 100A or more.

Do you know of any companies that sell a separate CAM box (thru) with main breaker?? This would allow me to tie it into my distro without having to figure out how to squeeze it in where I have no space now.

Thanks
Neil

You really should have a main breaker in your distro.

The upstream breaker is designed to protect the downstream wiring.  In your specific case, if you have #2 SC cable, you need to have an upstream breaker at <195 amps.  If you have some other kind of #2 cable such as multi-conductor SOOW cable, this number is different and almost certainly significantly lower than 195 amps, and there may be other problems with your setup; e.g. it is not allowable to break out SOOW cable into camlok connectors.

If you are drawing power from a 100A main breaker, you will have 2 legs of up to 100A/120V available each, or 200A/120v total.  If you are using 208/240v loads, you will have 208/240v/100A available, or whatever combination is in between.

The 400A breaker is definitely not acceptable for your situation.  Even if you aren't intentionally pulling 400A, one or more faults could exceed the rating of some component(s) in your system and you would be in big trouble.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 21, 2016, 05:42:46 pm
Thanks Tom for the info !!! Yes I am using SC cable (#2) which is good for 190A. I hear you on the main breaker thing, but most of the companies who make custom distro panels usually don't have or sell a main breaker for the distro, including my distro, not really sure why. I guess they don't want to limit the distro as it all depends on which wire and application the distro will be applied.

In my case, I have 8 X 15A mini breakers and 8 X 20A SqD breakers all tied to Edison outlets on panels, and underneath the panels, all wiring from all breakers tie straight into the CAMS. My suitcase style case doesn't even have room for another panel to house a main breaker.

But I hear you loud and clear, the main breaker protects the total capacity of the feeder, in my case #2 / 190A, when tying into a higher panel like a 3-phase 100A or more.

Do you know of any companies that sell a separate CAM box (thru) with main breaker?? This would allow me to tie it into my distro without having to figure out how to squeeze it in where I have no space now.

Thanks
Neil

Motion Labs makes stand-alone breakered disconnects.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 21, 2016, 06:34:23 pm
Thanks Mark, will look into the Motion Labs box, although I think I read somewhere that their smaller box is $600, and while that is probably very reasonable in the entertainment industry, I am using this probably 1-2 times per year for specific parties at big halls.

When I use my distro at home, I know the limits of my cable, and end up cabling it directly (temporarily) to a SqD breaker within my home panel, for 1 specific event that takes a lot of juice. Assuming that my breaker is sized correctly to the feeder cable, I think I should be fine there without needing an expensive breakered disconnect, as the main (sized) breaker in my panel becomes that disconnect for me.

But for this bigger event in the hall with the 100A 3-phase panel, I think that is where I will need it more, and am hoping that I can find a more affordable solution. Reached out to the guys at AMPSHOP to see if they have something a little more reasonably priced. Sadly I have no more room in my distro to add a main breaker panel, so it will have to be an external CAM solution between the main source and my distro.

Thanks for all the support !!

Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Tim McCulloch on January 21, 2016, 07:35:57 pm
#2 is only rated for 195 amps IF you can have 75 C cable temperature and that all the lugs it is connected to are rated for that temp or higher.

There is a rating for #2 at as little as 85 amps.  Do not presume that your feeder can universally be used for a constant load of 195 amps.

I will have to go back and read Tom's post, but a master breaker in your distro only prevents a feeder overload from the circuits in your distro, it does nothing to protect from short circuits due to physical damage to the feeder.  In the venue you are discussing you should hook up to the 100 amp service.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 21, 2016, 11:44:55 pm
Thanks Tim for this useful feedback. You have peaked my curiosity though. If a breakered disconnect between feeder and distro is to protect from overload on the distro (and hopefully lined up with feeder capacity as well), then is it not the job of the breakered 100A main panel to protect the feeder (and everything else down the line) if a short occurs on the feeder as you suggest ??

From most of the installs I have seen, it is Breakered Main Panel => CAMS feeder => Breakered Distro (yes I realize there are more elaborate setups with stringer boxes and 20A/30A/50A sub feeds, but more or less that is what I have seen. So if you assume one is using a breakered distro or breakered disconnect between feeder and distro, what other protection would you build into the design post main panel ??

Thanks again !!

#2 is only rated for 195 amps IF you can have 75 C cable temperature and that all the lugs it is connected to are rated for that temp or higher.

There is a rating for #2 at as little as 85 amps.  Do not presume that your feeder can universally be used for a constant load of 195 amps.

I will have to go back and read Tom's post, but a master breaker in your distro only prevents a feeder overload from the circuits in your distro, it does nothing to protect from short circuits due to physical damage to the feeder.  In the venue you are discussing you should hook up to the 100 amp service.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 22, 2016, 12:18:15 am
I usually work with installs, but it is common if a feeder is protected upstream by an appropriate breaker and the panel (distro) is rated for at least what the upstream breaker, then a main breaker is not needed in the panel or distro.  That said, there might be some convenience to having the disconnect locally at the distro than x feet away.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: David Buckley on January 22, 2016, 06:31:49 am
I have a suitcase style single phase distro that has a mix of single 15A and 20A breakers and outlets. The venue I am setting up in has 3 phase power, so my plan is to tie in my black and red, and cap or tape the blue leg.

As a non-American, I'm just a tad confuzzled here.  You have a single phase distro; does this mean it is 110V only, so a black hot and white neutral plus ground connection to your power, or is it 110V split phase, which has two hots, one neutral, and a ground?


Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Keith Broughton on January 22, 2016, 06:35:49 am
but most of the companies who make custom distro panels usually don't have or sell a main breaker for the distro,


Really?
All of the Motion Labs distros we have include a main breaker rated at the capacity of the feeder cable.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mac Kerr on January 22, 2016, 06:52:50 am
As a non-American, I'm just a tad confuzzled here.  You have a single phase distro; does this mean it is 110V only, so a black hot and white neutral plus ground connection to your power, or is it 110V split phase, which has two hots, one neutral, and a ground?

Single phase has 2 hot legs on the same phase, but with opposite polarity. It has 240V between hot legs, and 120V between either hot and neutral.

Mac
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 07:47:29 am
Hmm, curious again here, and thanks for pointing me to Motion Labs, seems like they do have Main Breakers on their distro designs. When I was shopping around for distros, like mine (suitcase style), I guess the company assumed I had another breakered disconnect, because in their designs, no main breaker on the distro.

When I had to expand my distro, I opened it up to add a 2nd plate of breakers, and noticed the distro company simply wired all of the breakers with single solid copper straight into the CAMs, so basically the CAM nut ties down all the copper going to the breakers.

Now if I was to figure a way to get a main breaker panel in there, I would assume I would have to use some SC cable internally to jump the CAMS to the main breaker, but then from there, how would one tie 16 breakers worth of copper to the main breaker ??

At that point, I would imagine there is a way to safely get some bus bars in there huh. Again, in my case, it is a suitcase style with metal lining, so might be tough to get bus bars in there.

Any ideas how it is done internally when introducing a main breaker?

Thanks guys !!
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 07:54:42 am
Is there a way to post pictures here, other than include a link to a hosted picture ? I just found pictures of my distro including a shot of the rear panel all wired up internally, would make for a better conversation if I could include the pics here. In the meantime, will find somewhere to upload it.

Hmm, curious again here, and thanks for pointing me to Motion Labs, seems like they do have Main Breakers on their distro designs. When I was shopping around for distros, like mine (suitcase style), I guess the company assumed I had another breakered disconnect, because in their designs, no main breaker on the distro.

When I had to expand my distro, I opened it up to add a 2nd plate of breakers, and noticed the distro company simply wired all of the breakers with single solid copper straight into the CAMs, so basically the CAM nut ties down all the copper going to the breakers.

Now if I was to figure a way to get a main breaker panel in there, I would assume I would have to use some SC cable internally to jump the CAMS to the main breaker, but then from there, how would one tie 16 breakers worth of copper to the main breaker ??

At that point, I would imagine there is a way to safely get some bus bars in there huh. Again, in my case, it is a suitcase style with metal lining, so might be tough to get bus bars in there.

Any ideas how it is done internally when introducing a main breaker?

Thanks guys !!
Hmm, curious again here, and thanks for pointing me to Motion Labs, seems like they do have Main Breakers on their distro designs. When I was shopping around for distros, like mine (suitcase style), I guess the company assumed I had another breakered disconnect, because in their designs, no main breaker on the distro.

When I had to expand my distro, I opened it up to add a 2nd plate of breakers, and noticed the distro company simply wired all of the breakers with single solid copper straight into the CAMs, so basically the CAM nut ties down all the copper going to the breakers.

Now if I was to figure a way to get a main breaker panel in there, I would assume I would have to use some SC cable internally to jump the CAMS to the main breaker, but then from there, how would one tie 16 breakers worth of copper to the main breaker ??

At that point, I would imagine there is a way to safely get some bus bars in there huh. Again, in my case, it is a suitcase style with metal lining, so might be tough to get bus bars in there.

Any ideas how it is done internally when introducing a main breaker?

Thanks guys !!
Title: Adding attachments
Post by: Mac Kerr on January 22, 2016, 07:58:46 am
Is there a way to post pictures here, other than include a link to a hosted picture ? I just found pictures of my distro including a shot of the rear panel all wired up internally, would make for a better conversation if I could include the pics here. In the meantime, will find somewhere to upload it.

At the bottom of the posting window is a button called "Attachments and other options". Click that and you will be able to add up to 5 photos to any post as long as the total size does not exceed 512KB.

Mac
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 22, 2016, 09:29:04 am
Hmm, curious again here, and thanks for pointing me to Motion Labs, seems like they do have Main Breakers on their distro designs. When I was shopping around for distros, like mine (suitcase style), I guess the company assumed I had another breakered disconnect, because in their designs, no main breaker on the distro.

When I had to expand my distro, I opened it up to add a 2nd plate of breakers, and noticed the distro company simply wired all of the breakers with single solid copper straight into the CAMs, so basically the CAM nut ties down all the copper going to the breakers.

Now if I was to figure a way to get a main breaker panel in there, I would assume I would have to use some SC cable internally to jump the CAMS to the main breaker, but then from there, how would one tie 16 breakers worth of copper to the main breaker ??

At that point, I would imagine there is a way to safely get some bus bars in there huh. Again, in my case, it is a suitcase style with metal lining, so might be tough to get bus bars in there.

Any ideas how it is done internally when introducing a main breaker?

Thanks guys !!
Neil, it's good practice to have a main breaker on your distro.  This accomplishes several things:

- it allows you to use the short tap rule without an external breaker - i.e. if you had a 100A breaker in your distro and your feeder cable was 10' or shorter, you could legally tie in to the 400A switch
- If something goes wrong, you have one place to shut off your power, rather than needing to flick a bunch of branch breakers (caveat - you don't want to make a habit of switching your main breaker on or off under load, but in an emergency, it's nice to have)
- It provides a nice way to ensure that all downstream power is indeed off, as with a bunch of branch breakers, something might be missed and still be live, which could be problematic for switching the company switch off, etc.

None of these things are life or death and as others have mentioned, the most important function of a main breaker is to protect the feeder cable itself - something that can only be completely done at the beginning of the feeder and therefore not internal to your distro, but safety in electrical distribution is accomplished with multiple layers of insurance, and having a main breaker on your distro is definitely nice to have.

In your situation, I wouldn't go out of your way to modify your distro.  Doing it yourself is likely worse than not having a main breaker from a liability perspective.  As long as you are using the correct cable - SC and not welding cable or SOOW broken out into individual cams, and you are plugging into a feed that is breakered below the maximum capacity of your downstream equipment, you're in pretty good shape.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 10:12:58 am
Loving the feedback, so many people willing to share their best practices and guidelines, great forum !!!

Here are a few shots of my distro, when I first received it. This was the initial panel, which has 8 X 15A circuits with mini breakers. Since I needed more circuits, I have since swapped out the 2U blank panel above it with an 8 X 20A SqD panel. I then split the Edison outlets so I could have a total of 16 circuits. Now keep in mind, I am not using all of them to their full capacity, as I realize that I am maxed based on feeder and panel source. I calculate my load according to the feed.

BUT, if one just blindly looked at the number of circuits here, I think one would highly recommend a main breaker, to ensure the total is not surpassed, as there are enough circuits to easily do that. But as you can see, the only way I could squeeze in a main breaker is to get rid of my 2U SqD 8 breaker panel (where the blank panel sits in this shot), replace it with the main one, and then somehow redesign this bigger panel to house a huge row of 16 X SqD breakers with the CAMS.



Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 22, 2016, 10:26:07 am
Loving the feedback, so many people willing to share their best practices and guidelines, great forum !!!

Here are a few shots of my distro, when I first received it. This was the initial panel, which has 8 X 15A circuits with mini breakers. Since I needed more circuits, I have since swapped out the 2U blank panel above it with an 8 X 20A SqD panel. I then split the Edison outlets so I could have a total of 16 circuits. Now keep in mind, I am not using all of them to their full capacity, as I realize that I am maxed based on feeder and panel source. I calculate my load according to the feed.

BUT, if one just blindly looked at the number of circuits here, I think one would highly recommend a main breaker, to ensure the total is not surpassed, as there are enough circuits to easily do that. But as you can see, the only way I could squeeze in a main breaker is to get rid of my 2U SqD 8 breaker panel (where the blank panel sits in this shot), replace it with the main one, and then somehow redesign this bigger panel to house a huge row of 16 X SqD breakers with the CAMS.
Neil, there's a significant problem with the construction of your distro.   The lugs for each cam connector are designed for one wire, but instead, have all of the branch wires jammed in there under one screw.  This isn't acceptable, as the lug wasn't designed to keep tension on multiple small wires.  This will exacerbate the problems due to expansion and contraction from heat.  You will find yourself with loose lugs, high voltage drop, and burnt wires if you keep using your distro this way.

I'm curious - did AmpShop make this for you?  I know they are favored on here due to price, but I've also heard rumors of shoddy construction.  If they made this, that shoe fits.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Cailen Waddell on January 22, 2016, 10:27:25 am

Loving the feedback, so many people willing to share their best practices and guidelines, great forum !!!

Here are a few shots of my distro, when I first received it. This was the initial panel, which has 8 X 15A circuits with mini breakers. Since I needed more circuits, I have since swapped out the 2U blank panel above it with an 8 X 20A SqD panel. I then split the Edison outlets so I could have a total of 16 circuits. Now keep in mind, I am not using all of them to their full capacity, as I realize that I am maxed based on feeder and panel source. I calculate my load according to the feed.

BUT, if one just blindly looked at the number of circuits here, I think one would highly recommend a main breaker, to ensure the total is not surpassed, as there are enough circuits to easily do that. But as you can see, the only way I could squeeze in a main breaker is to get rid of my 2U SqD 8 breaker panel (where the blank panel sits in this shot), replace it with the main one, and then somehow redesign this bigger panel to house a huge row of 16 X SqD breakers with the CAMS.

I've never seen wire run from a panel mount cam lock quite like that before.  Someone with more knowledge might jump in here but I would think it would be safer/prudent to use a single piece of large wire to a bus bar then to individual breakers. 

Does the rack have a metal back box on the inside?  I don't see a ground wire coming off to ground the back box...  Surely it isn't just raw wood on the inside.  One loose wire could energize  a rivet or handle...


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Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 10:39:02 am
Yes the road case is fully lined with a metal liner all around. Honestly, it's been a few years since I ordered this from a company in the US that makes distros, this was a more compact design to be portable. To be honest with you, I was actually impressed with the wiring done under the panel, in terms of connectors and cleanliness, but I hear you on cramming all the wires onto the CAM lugs. Since my roadcase is so small, I cannot imagine how bus bars could be mounted underneath without touching the metal liner of the case. I honestly don't use this panel more than twice a year for a huge home haunt (very high end and technical one). I am now DJ'ing a huge party for my son's school (truss, MACs, QSC, the whole nine) and will need a lot of power, so figured I would bring along my distro to tap into the hall's feed. I have used this panel for close to 8 years now without an issue, no loose lugs, etc...

If I had to do it all over again, I would probably order something new that is more secure and conforms to code better. But I don't plan on tossing this investment in the garbage, so looking for suggestions where I can buy the parts to improve on it.

Keep in mind that to make matters worst, there are 8 more wires on top of the 8 already there tapped onto the CAM lugs, feeding 16 breakers. I definitely like the idea of using bus bars, but would have no idea how to safely mount it within the shallow case.

Worst case, even if it costs some bucks, might send the case to Motion Labs for a rework.

Thanks
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 22, 2016, 11:08:29 am
A couple of thoughts-some really just observations.

You are calling this (I presume because the seller said so), a 100 amp distro.  In reality, there are a maximum of 4 20 amp circuits on a leg-so in reality an 80 amp distro.  Not a safety issue-but perhaps a bit of marketing optimism.

Apparently they are relying on the duplex receptacles being connect to the panel for a ground.  Practically, might be OK-certainly not best practice.  Far better to have a bonding wire to a lug.

From the pics, it appears that there should be plenty of room in the bottom of the box for bus bars, or purpose built terminal blocks.
Something like this would work very nicely:

http://www.cooperindustries.com/content/public/en/bussmann/electrical/products/power_distributionblocksterminalblocks/pdb_series_.html

Just run large wires down to blocks and then #12's back to receptacles-use stranded wire to make it easier to work with and open and close case.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 11:27:10 am
Stephen,

Not following you on the 80A 4 circuit comment. Essentially, according to my theory only, I could have as many circuits as I wanted to, based on the capacity of both the CAM as well as feeder cable. Hence why I expanded my 8 circuit design to a 16 circuit design.

From a pure breaker point of view, I have 8 X 20A plus 8 X 15A, total 280A, well under the 400A rating of the CAMS. Now, if I start to factor in the feeder (SC #2), then that 280A breaker availability falls down to 190A. So if I wanted to do things right, I would probably have to remove some breakers and outlets to ensure the max total does not pass the feeder capacity of 190A, so maybe 6 X 15A and 5 X 20A, and of course balance the load across both legs.

I like the distro block idea in your link, easy for me to incorporate, to install between CAMs and breakers. The model in your link breaks out the leg to 4 smaller connections, but what if I needed 6 or 8 ?? Do they carry blocks with more outputs ??

I guess I would have to rivet these blocks somehow to the inside of the case huh...

Thanks

A couple of thoughts-some really just observations.

You are calling this (I presume because the seller said so), a 100 amp distro.  In reality, there are a maximum of 4 20 amp circuits on a leg-so in reality an 80 amp distro.  Not a safety issue-but perhaps a bit of marketing optimism.

Apparently they are relying on the duplex receptacles being connect to the panel for a ground.  Practically, might be OK-certainly not best practice.  Far better to have a bonding wire to a lug.

From the pics, it appears that there should be plenty of room in the bottom of the box for bus bars, or purpose built terminal blocks.
Something like this would work very nicely:

http://www.cooperindustries.com/content/public/en/bussmann/electrical/products/power_distributionblocksterminalblocks/pdb_series_.html

Just run large wires down to blocks and then #12's back to receptacles-use stranded wire to make it easier to work with and open and close case.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 11:34:06 am
Stephen,

Never mind on the question of a bigger bus/distro block design, I clicked on the link for model details and found that they also make a 6 and 12 output design. I guess I would most definitely need the 12 connection model for the neutral, although I would have to drop the number of circuits down from 16, which I probably should do anyways to line up nicely with feeder and main breaker capacity.

http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/product-literature/bus-ele-pp-3134-pdb


Stephen,

Not following you on the 80A 4 circuit comment. Essentially, according to my theory only, I could have as many circuits as I wanted to, based on the capacity of both the CAM as well as feeder cable. Hence why I expanded my 8 circuit design to a 16 circuit design.

From a pure breaker point of view, I have 8 X 20A plus 8 X 15A, total 280A, well under the 400A rating of the CAMS. Now, if I start to factor in the feeder (SC #2), then that 280A breaker availability falls down to 190A. So if I wanted to do things right, I would probably have to remove some breakers and outlets to ensure the max total does not pass the feeder capacity of 190A, so maybe 6 X 15A and 5 X 20A, and of course balance the load across both legs.

I like the distro block idea in your link, easy for me to incorporate, to install between CAMs and breakers. The model in your link breaks out the leg to 4 smaller connections, but what if I needed 6 or 8 ?? Do they carry blocks with more outputs ??

I guess I would have to rivet these blocks somehow to the inside of the case huh...

Thanks
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 12:32:03 pm
Neil,

Are you perhaps overlooking the fact that each of the feeder cables and cams is individually rated?  With a 100 amp single-phase (a/k/a split-phase) service, both of your hot leg #2 feeder cables will carry 100 amps safely. At the distro (where there typically would be a double pole 100 amp OCPD), you have available 200 amps of 120 volt AC power.  (Two legs of 100 amp service.)  From some of your comments, you appear to be doubling the needed ampacity of the feeder.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 01:36:16 pm
Thanks for the reply Mark !! Yes I am aware that if I hook up to a 3-phase 100A, and only use 2 legs, each leg will have 100A capacity totaling 200A. Since I am thinking of adding a main breaker to my distro (if space permits), I need to figure out what size main breaker to go with, based on feeder size and 16 installed breakers. So to help clarify my area of focus where I am looking for feedback:

1) Feeder is a #2 SC, Distro has Series 16 Cams, with 8 X 15A and 8 X 20A breakers. What size main breaker does one install. Assuming correct temperature for feeder, rating says 190A. A double 100A main would be too small, as I have more capacity on the feeder (assuming temp ok). A double 200A would bypass the rating of the cable by 10A, and odds are not recommended. So what is the in-between breaker size to go with for distro mains (I wish they sold a double 190A) ??

2) I currently have 8 X 15A and 8 X 20A breakers and outlets on the distro. If I maxed (which I usually don't) each circuit, that would total 280A across both legs on single phase (140A per leg if balanced). My feeder can handle that, so want to make sure my main breaker is sized properly so I can take advantage of all 16 circuits presently installed. Perhaps if my max is 140A on breakers per leg, a double 150A for main breaker might be appropriate here.

3) Chassis ground. Some have suggested that my ground in my distro right now is only between outlet and chassis. If I am to run a better ground connection between CAM lug and chassis, what size wire should I use internally (#2 SC ?), and is it simply a matter of tapping that wire onto the metal lining of the inside case ?

Thank you for your time !!

Neil

Neil,

Are you perhaps overlooking the fact that each of the feeder cables and cams is individually rated?  With a 100 amp single-phase (a/k/a split-phase) service, both of your hot leg #2 feeder cables will carry 100 amps safely. At the distro (where there typically would be a double pole 100 amp OCPD), you have available 200 amps of 120 volt AC power.  (Two legs of 100 amp service.)  From some of your comments, you appear to be doubling the needed ampacity of the feeder.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 02:11:14 pm
Neil, if I am reading your posts correctly, you have 16 individual #12 (or #14) AWG conductors stuffed into each of the lugs on the cam connectors. (Eight from the original construction, and eight more that you added.)  If so, and with all due respect, I would not personnally want to use your distro. I recognize that you have not had any problems to date, but there is a lot of energy present inside there. The lugs are not designed for that use. Bus bars are designed for attaching individual wires.

I respectfully suggest that rather than trying to retrofit your distro you should get a well-designed, UL or ETA listed distro of appropriate size for your needs.  If you don't use it very often, rental might be a more cost-effective solution than buying a distro. If you decide to keep using your distro, you should review your insurance coverages (liability, home, and life insurance) with your agent.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 02:31:57 pm
Yup, agreed, and already a step ahead of you, based on recommendations here, I will be ordered three Square D 264108 double pole 8 branch connecting blocks. The 8 branch blocks will allow me to feed the 2 legs to each group of 8 breakers, and the 2 remaining double pole 8 branch will allow me to feed up to 16 neutral and ground connections to the outlets. Great idea, this takes care of the branch wiring. Sad that a professional distro company was selling this stuff like this, there are probably dozens of guys out there with the same setup as me.

So that takes care of that. Now for the ground. Assuming I have a block in place, can I simply use a #12 or #14 off the block and tapped onto the case chassis, or do I need to have a #2 SC coming off the CAM lug to the chassis ?

With those things out of the way, I just have to hunt down someone who sells a 1U panel with a cutout for a main breaker. Most main breaker panels I see from the likes of Motion are 3U and does not fit in my setup.

On a side note, if you take a look at the distros coming from PSS (ampshop), at least the distros they show on their site, there is no main breaker, only the individual circuits are breakered. So no surprise that there is none on mine when I ordered it way back when.

Thanks for all your help (and honesty), much appreciated !!

Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 02:34:51 pm
And just to be sure, is it ok to use a couple pieces of #2 SC from the CAM lugs to the distro blocks, or do I need to go get some short length of #2 solid copper for the jumps (which will probably be harder to work with in such a tight space).

Thanks
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Tim McCulloch on January 22, 2016, 02:41:31 pm
And just to be sure, is it ok to use a couple pieces of #2 SC from the CAM lugs to the distro blocks, or do I need to go get some short length of #2 solid copper for the jumps (which will probably be harder to work with in such a tight space).

Thanks

#2 THNN or similar.  Type SC is rated only for portable use.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 22, 2016, 03:24:21 pm
The distro blocks I mentioned are a UL listed method for connecting many small wire to a larger source-easier to make sure it is right than a bus bar-they usually have an ampacity marked on them so no "engineering" involved.

As for the ground, you could use either another distro block, or change out the lug to one that has 2 holes or is designed for multiple condctors.  The size of the ground conductors depends on the breaker protecting the distro-so I would size it according to the ampacity of your feeders and always use a proper breaker ahead of it.  So, if you are using 100 amps, #8 is sufficient, if you are using 200 amps I would use #4.

FWIW, the actual allowable conductors for those is impossible to tell from your pictures.  They should be stamped on the side with the allowable conductors.  So, for instance, they might say #10-250mcm and any conductor in that range is fine.  IF, they say something like 2-#6-4/0 then you could actually put two conductors of the same material (2 copper or 2 al-but NOT one AL and one Cu) in one-then you could use one to bond the chassis and one to go to your ground distro block.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 03:49:59 pm

(Snip)

When I use my distro at home, I know the limits of my cable, and end up cabling it directly (temporarily) to a SqD breaker within my home panel, for 1 specific event that takes a lot of juice. Assuming that my breaker is sized correctly to the feeder cable, I think I should be fine there without needing an expensive breakered disconnect, as the main (sized) breaker in my panel becomes that disconnect for me.

(Snip)

Neil

The above statement makes me ask: How do you tie in at home?  Do you have an unused dual pole breaker (OCPD) that you tie to?  What is the ampere rating on that breaker?  Are you using the #2 SC feeder cable for the tie-in?
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 04:33:24 pm
Mark, I see where you are going with this question, and can anticipate the answer :-) In all honesty, since it is up temporarily for Halloween in my closed basement, yes, I tie the SC feeder straight into the home panel in an unused 100A dual pole breaker.

My guess, the proper way to do this would be to use solid copper in a conduit from the main home panel/breaker to a dedicated CAM box, with the 100A disconnect breaker in the home panel to control the CAM box, and then my SC would tie into the CAM box. But since this is a home, I thought it would be overkill to have a CAM box screwed onto my basement/cinema room wall for a whole 2 days (Halloween) worth of use.

But I hear you on the whole code, liability, insurance thing. 10 years running, and always cross check my wiring. Please don't scold me :-)

Already have my distro apart after this conversation, and figuring out where I will be mounting my distro blocks. Ordered 3 double pole 1 X 8 SqD, one double pole for both legs, 8 feeds to 8 breakers each, and then 1 double pole each for 16 feeds of neutral and ground to the outlets.

Hoping it is ok to screw thru the case and metal lining to be able to mount the blocks solidly.

For the ground, can I purchase a replacement lug only for the ground CAM, without replacing the entire CAM panel mount, giving me a 2 wire connection, one for the distro block and one for the chassis ground ??

The other option I have to look into, is getting a 2 X 8 distro block for the ground, that allows 2 connections on the feeder side. This way I can go from CAM to distro block and back out to chassis for the ground.

Thanks

The above statement makes me ask: How do you tie in at home?  Do you have an unused dual pole breaker (OCPD) that you tie to?  What is the ampere rating on that breaker?  Are you using the #2 SC feeder cable for the tie-in?
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 05:49:47 pm
OK,

All distro blocks ordered, and figured it all out. I ordered 1 double pole 1-In x 8-Out which covers me for the 2 legs, each pole feeding 8 breakers with a mix of 15A and 20A plugs (16 total). Then I ordered 1 double pole 2-In X 8-Out, which allows me to jump both poles for the Neutral and Ground to give me 16 outs (for my 16 outlets), and a remaining jump to chassis ground. All done with SqD 9080 blocks.

Thanks guys for this discussion, really cleared things up, and now my CAM and internal wiring will be much better and a better ground to boot.

I am of course still stuck for where to put that main breaker. Assuming that my power blocks won't come up too high, I have approx. 1.5U worth of blank space in my rack to house a main breaker. Sadly a 2U won't fit and a 1U will probably be too short for a main double breaker.

Do you guys know if Motion or PSS sells main breaker panels that small ?? If not I will have to go with an external breakered disconnect, no choice.

Thanks
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 05:59:53 pm
Sounds like a heckuva Holloween party/haunted house.  And I can well imagine that somewhere out there folks are doing similar things with much scarier home-built contraptions ....
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 07:08:01 pm
While on the subject of using the distro at home, we are getting into a big reno for the 1st floor, kitchen cabs, ceramic, the whole nine. I need to run new circuits here and there and my current 40 space panel is already full, already using double mini breakers. So part of the reno will be to swap out my 40 space for a 60 space panel. My electrician cousin keeps telling me, rather than opening up the house panel once a year to tap my distro on there, to install a CAM box next to the panel. Since I am doing the reno, I an thinking of finally doing it.

Assuming that I use THNN in conduit from the home panel to the CAM panel, off of a 100A breaker, do you have any suggestions for COMPACT CAM panels I could use. Of course to keep things safe, I would like to have a lock on it so nobody goes inside of it (nobody would but you never know). The CAM panels I see are quite industrial looking and big, but I recall seeing a nice compact rectangular one just wide enough to hold the CAM panel mounts.

Suggestions ??

Sounds like a heckuva Holloween party/haunted house.  And I can well imagine that somewhere out there folks are doing similar things with much scarier home-built contraptions ....
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Cailen Waddell on January 22, 2016, 07:28:22 pm

Sounds like a heckuva Holloween party/haunted house.  And I can well imagine that somewhere out there folks are doing similar things with much scarier home-built contraptions ....

My group sets up and runs a haunted house for the municipality I work for.  We out through hundreds of people every night, fully lit immersive experience with fog pneumatics, etc.  We use 4 20amp circuits. 


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Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 11:02:35 pm
Cailen,

Nice to see others enjoying the hobby as well. Before I even get into the pneumatics and animatronic side, which is a thread in itself, here is just a short summary of some of the gear I run off of my distro for our home haunt, which attracts over 5000 people (fundraiser for Children's Wish). In all honesty, I have digital ammeters on my feeder lines and on average pull about 70-80 amps total, but that excludes my 60-gallon 2-stage compressor feeding all the pneumatic props. BTW, it is a 2 month setup, running on a custom DMX computer, triggered by 16 industrial photoelectrics.

2 X Martin Atomic 3000's
2 X Martin Magnum 2000's smoke
1 X ADJ Fog Storm 1200
6 X 10W Quad LEDs (used to be PAR56 500w several years ago)
2 X QSC K181 subs (FOH)
2 X QSC K12 tops (FOH)
2 X QSC K10 tops (side fill down the street)
2 X QSC K10 tops (2 props)
8 X Gemini tops (8 props)
1 X Pyle 8 channel amp (8 props)
2 X Epson projectors (window animations)
5 X DMX 4-ch packs (2 circuits props)
14 X PAR38 150w spots (for props)

I think you get the idea, lots of other stuff that probably make up a couple of other circuits, but there is a LOT of juice being pulled here, on a lot of circuits, hence the distro :-)

Neil




My group sets up and runs a haunted house for the municipality I work for.  We out through hundreds of people every night, fully lit immersive experience with fog pneumatics, etc.  We use 4 20amp circuits. 


Sent from my iPhone using Tapatalk
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 11:07:32 pm
I see no point in using series 15 cams (150A) at home when your distro and existing feeder uses series 16 (400A) cams. I suspect that it likely be cheaper, neater, and easier to have a smaller panel box made than to mess around with adapters or a special set of feeders that are series 15 on one end and series 16 on the other. If you buy a stand-alone breakered disconnect (from Motion Labs or somebody else), it will no doubt come with series 16 cams, too.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 11:12:00 pm
Jumping back on topic for doing a main breaker on my distro, as I mentioned, and as per previous pics in this post, I have a 5U panel housing the CAMS, 8 Edison outlets (16 circuits) and 8 mini breakers, and another 2U panel housing 8 more breakers, leaving me with 1.5U left blank in my case, probably not enough to get a main breaker in there, especially if I will be using that dead space underneath to now mount my power distro blocks to feed the CAMS to the breakers to improve the design.

What if I was to get rid of my 2U 8 breaker panel, and replace it with a 2U 20 breaker panel, like the one sold by PSS (ampshop).
http://www.ampshop.com/parts.html

Their panel would allow me to maintain my 16 breaker setup, and leaves me with 4 free spaces. From a code and setup point of view, could I use 2 of those spots to slap a 100A double pole main breaker in there ? Does it matter that the main breaker is in line with the circuits physically? Technically it should not matter.

My only technical challenge is that their breaker panel is made for QOU breakers, and I believe those only go up to 60A. Would have to figure out a way to mount a double pole 100A within that same cutout. I guess I could talk with those guys to see if they could even mount it for me (custom cutout), sell me the panel setup already with the breakers on it.

Thoughts on this ??
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 11:21:43 pm
Curious Mark, why would it matter ?? If I have series 16 cams on my distro, fed by a #2 SC into a breaker in my home panel (or pretend it was fed into a series 16 cam panel tied by solid copper into my home panel for argument sakes for code). To me, the series 16 allow me to go up to 400A (feeder permitting), but is simply overkill for only using less than 100A, perhaps justifying your comment for the series 15 CAMS.

BUT, I would like to be able to do exactly what I mentioned in my previous replies, carry my distro to a hall, and setup a club worth of gear and use the venue's 3-phase panel and tie into it. This way I can max out the #2 SC feeder capacity of 190A (in a perfect environment), or whatever main breaker I end up adding that is close or under the capacity of the feeder.

The series 15 CAMS would limit me even further, so would prefer having the series 16 for the occasional gig that requires a little more juice.

But agree, way overkill for my home haunt application.

I see no point in using series 15 cams (150A) at home when your distro and existing feeder uses series 16 (400A) cams. I suspect that it likely be cheaper, neater, and easier to have a smaller panel box made than to mess around with adapters or a special set of feeders that are series 15 on one end and series 16 on the other. If you buy a stand-alone breakered disconnect (from Motion Labs or somebody else), it will no doubt come with series 16 cams, too.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 11:29:00 pm
You have 3U (or 3.5U) to work with, so a custom panel might do it for you. Whether that (and all of the additional rework/new parts) is cost-effective is your call, however.  Ampshop does not build UL/ETA listed devices (to the best of my knowledge), even if they use listed components. Given that you are running a commercial (albeit not-for-profit) attraction, you might want to factor that in to your decision. YMMV.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 22, 2016, 11:41:27 pm
No one has addressed your question on breaker size.  For installs, with a feeder ampacity of 190 amps (I am assuming you have that correct-more to consider than just the wire rating out of a chart), it is acceptable to use a 200 amp breaker.  The NEC lists standard breaker sizes, and under 800 amps it is permissible to round up to the next larger size.

Permissible does not necessarily mean smart; however, the trip time between a slight overload on a 190 vs a 200 will not be much-and likely your peaks would start tripping the 200 if you got to close with your continuous load.  If you were pulling 195 amps on resistive heating that might be different-but those types of scenarios require othe considerations and derating.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 22, 2016, 11:52:26 pm
Thanks Steve for answering this last part of the puzzle for me. I was just brainstorming this very subject with a technical buddy of mine, and while he suggested a 200A main breaker should be fine, for the small difference per leg, he was not sure 100% and neither was I. Did not know that part of the code that allowed rounding up for small differences. That is good to know, but again, I am not stupid here, even if I slap a 100A double pole main, I will always try to remain below the capacity of the feeder, even if it is only a 10A drop on a good day.

Now I just have to figure how to get a double pole 100A onto the same panel with 16 QOU breakers.

Maybe one of you know this already. The SqD breakers I have right now, some say Series 2 others say Series 3. I assume they are part of the same QO family. The Ampshop panel says their panel is for QOU breakers, would I be able to reuse my existing Series 2 and 3 breakers in that panel ?? Hoping yes to save some coin and just transfer over what I already have.

The way my current panel is made, they used 2 long screws and a back mounting bar to group 3 breakers together, to hold it up to the panel it is mounted on. Will be curious to see how ampshop keeps 20 breakers mounted to the panel, hoping it is not just 1 long metal bar across all of them. Only reason I ask is to see if I can reuse mine and how they would mount due to the different Series design, and how that would mate with the remaining breakers ampshop would provide for me on that panel.

Thanks

No one has addressed your question on breaker size.  For installs, with a feeder ampacity of 190 amps (I am assuming you have that correct-more to consider than just the wire rating out of a chart), it is acceptable to use a 200 amp breaker.  The NEC lists standard breaker sizes, and under 800 amps it is permissible to round up to the next larger size.

Permissible does not necessarily mean smart; however, the trip time between a slight overload on a 190 vs a 200 will not be much-and likely your peaks would start tripping the 200 if you got to close with your continuous load.  If you were pulling 195 amps on resistive heating that might be different-but those types of scenarios require othe considerations and derating.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mark Cadwallader on January 22, 2016, 11:54:48 pm
Yes, series 16 is overkill at your home, but not for some future 200A usage. You mentioned using series 15 at home (for a smaller box on the wall in your basement). While having non-standard hybrid 15/16 adapter feeder made for home use would be fine, you could never use them to connect (as an extension) with your existing 16 series tails (which you use away from home).  I personally would go with the series 16 to standarize my gear and increase the inter-operability of my stuff. 
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 24, 2016, 11:20:29 am
Just wanted to say thanks to Mark, Tim, Stephen and others that took the time to engage in this useful conversation with me. Rather than slap the code book on me, you walked me thru some much needed upgrades, that, after stepping back and looking over the distro, is very needed.

While the distro worked all of these years, it was pretty much in my garage for a short duration. But now that I am carrying it into a huge hall to power a lot more thirsty gear, I think the upgrade timing is perfect.

Final game plan, already ordered a few power distro blocks from SqD, double pole 1 X 8 for the 2 legs to feed 8 outlets each, a double pole 1 X 8 (2) to feed 16 Neutrals and a single pole 1 X 8 to feed 8 Grounds.

I think I am also going to re-work my panels, keeping the big 5U panel that houses a mix of CAMS, mini breakers (15A), and outlets, and simply not use the 8 mini breakers anymore. Then I will swap out my 2U 8 SqD breaker panel for a 3U 20 breaker SqD panel, filling only 16 spaces with breakers, and using the remaining 4 space for a main breaker, and from discussions on here, seems a double pole 200A should do the job to protect my #2 SC.
 
Also, having seen the color coded outlets (available from Ampshop), I think I am going to re-group my outlets I have now, since they are already physically grouped in 2 groups of 4, I will probably re-wire for each group to tie to a leg. Will make balancing a lot easier to view, just like those color coded outlets.

The only worry in the upgrade is having to fit those big power distro blocks underneath in the case, and hope the top of them do not interfere with the items on the panels (breakers, CAMs, etc).
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 24, 2016, 11:26:51 am
And one more thing, assuming the main breaker that winds up in my distro is a double pole 200A, and the #2 SC is capable of 190A (in a perfect environment), then when I hook up my distro to the hall's 3-phase 100A panel, and use only 2 legs, that means that my total capacity is limited by their panel's breaker and not mine. Meaning my main is 200A and their main is 100A, giving me up to 100A per leg available. Does this make sense ??
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Tim McCulloch on January 24, 2016, 02:33:02 pm
Yes.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: David Buckley on January 24, 2016, 04:44:58 pm
Whats the make and model of those mini-breakers?
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 24, 2016, 11:09:19 pm
Potter & Brumfield
W92-X112-15

From the looks of it, it originally was a double pole, but was stripped to work as single pole, at least according to the part number and info I found online. When looking closer in my distro, 2 mini breakers are taped together. By moving to a full panel of SqD 20A, I will leave these 8 Mini Breakers in my distro but not use them. If I pulled them to sell them, I would be left with 4 double cutouts in the panel, which would not be too safe, and would not be too sure how to cover the holes, so might as well just leave the mini breakers there to cover up the space.

http://www.amazon.com/TE-CONNECTIVITY-POTTER-BRUMFIELD-W92-X112-15/dp/B00HQSJBMM

http://datasheet.octopart.com/W92-X112-15-Tyco-Electronics-datasheet-14490223.pdf

Whats the make and model of those mini-breakers?
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 25, 2016, 12:23:28 pm
Just got off the phone with PSS (Ampshop). They can make me a custom panel for my breakers, BUT, they cannot fit a 200A double main, as it is just too big for my suitcase style case, and will barely fit onto a 4U panel. In all honesty, between my home event and the dance coming up, I will probably only every be tapped onto a 100A (double) feed anyways, so there is no use in maxing out the main breaker in my panel to 200A, for the sole purpose of matching my #2 feeder. Expensive and takes up a lot of room for power I will probably never end up using.

Once I dropped down to a 100A main, then options were possible. There was talk of a GE main, but they will try to hunt down a SqD QOU 2100. According to them, these industrial QOU's are harder and harder to find. Which brings me to my next point.

I currently have a mix of Series 1,2,3 SqD QOU 20A. I was told the Series 1 has recalls on it, Series 2 is ok but the design is so-so, and the Series 3 is the most reliable. Of my 9 QOU's, only 5 are Series 3. They said, rather than spend the bucks on 11 more QOU's (plus my 5) for a total of 16 circuits, upgrade to all Westinghouse QCF 1020 compact breakers, for about the same price they could sell me the 11 QOU. By going this route, not only would I have a better breaker, but I would save room on the panel (smaller breakers) to house the main breaker as well.

So any thoughts of going with the QOU2100 as a main, as well as these QCF 1020's ???

They can basically cut me any breaker panel config I want, but am guessing these are the breakers they use and design with.

So in the end, I will toss my 5U panel I currently have (housing CAMs, 8 X 15A mini's, and 8 X Edisons), plus the 2U panel (housing 9 X SqD QOU 20A), and go this route instead:

2U with CAMS (re-use my CAMs, just buy the panel)
2U with 8 Edisons (re-use my Edison, just buy the panel)
4U with Breakers (QOU Main + 16 QCF 20A)

Thoughts ??

Thanks
Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Ray Aberle on January 25, 2016, 01:24:16 pm
Nothing wrong with using a 100A main breaker when you have #2 (single conductor) wiring, and you're certain you probably won't need the extra power in the future...

-Ray
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 25, 2016, 01:54:47 pm
Actually, when you consider that on long runs ampacity is only one issue-the major one being voltage drop, using "oversize" feeders is probably a smart thing to do-so I wouldn't consider the extra copper "wasted" by any means.

As far as breakers,  I know a lot of people that would find it hard to stomach a breaker being sold as "better" than Square D.  But I can't say I have first hand knowledge or that I have done side-by-side comparisons.  The Westinghouse/Sqhecy uare D sales pitch hits me more like what I would expect to hear if I took my Ford truck into a Chevy dealer with problems. "I can sell you an even better truck for not much more than fixing yours....."  Not sayin' it s a bad deal-just not sure that "better" is an absolute definition.  If they are a more functional form factor, that may be all the "better" that matters.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 25, 2016, 04:31:54 pm
Yeah, I think in my case, I can fit more breakers on a panel by going with the more compact Westinghouse QCF @ 0.5" wide than with the wider and slightly larger QOU SqD. Allows for some breathing room for the Main.

Now, drum roll, let me get you guys all worked up on here, especially those that play by the code book. And not to worry, so long as space permits, I will be installing all of those power distro blocks I ordered for a nice and secure connection off of each CAM.

BUT, speaking with the folks over at PSS (AmpShop), the guy there, who seemed to know what he was talking about, informed me that "by code", the only connection that requires to be split properly (physically) is the Neutral, since losing 1 Neutral wire while the hot is energized could cause some serious issues. But there was no issue, as far as he was concerned, and his understanding of the code, to wire all 8 leg/hot feeds (I have 8 circuits per leg) under the CAM lug. Same for the ground.

Like I said, as long as space is available in my case, I am going distro blocks all the way to be safe, but thought I would share this info with you guys, I am sure the responses will be interesting to say the least...
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 25, 2016, 08:50:41 pm
Well, code ALWAYS requires devices/lugs/equipment whatever to be used as "Listed".  The issue is not "splitting" the hots/neutrals, etc.  The issue is that the lug is "Listed" to be used only with the combination of conductors it was designed for-and that typically is marked on the lug.

Given the way I see panels/gear built, I seriously wonder what engineers are taught in college.  I recently installed a piece of equipment that, according to the engineer's advance information "required" 100 amps/3 phase/480 VAC-verbally verified the day before install.  Due to an ambitious install timeline, I had power roughed in about 175 feet-and wire cut to length (ie non returnable).  Once I got my hands on the equipment, I instantly realized something was way off-in fact it only required 30 amps/3 phase/480 vac.  Even better, the machine wiring drawing showed a 30 amp main disconnect with 60 amp fuses installed.  Yes, I make mistakes too, but this one cost $1500 extra on an install that should have been $2500 to begin with-and it shouldn't take a degree to know the difference between something using 30 amps and 100 amps-and this guy had done a lot of assembly on this equipment.

Bottom line, hearsay is hearsay-believe it and run by it if you want.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: David Buckley on January 25, 2016, 09:59:46 pm
Potter & Brumfield W92-X112-15

This might be a bit left field, but those breakers have an interrupt capability of 5KA.  I suspect that a 200A cam feed from a nearby transformer might have a prospective short circuit current (PSCC) capability in excess of 5KA if you get a short circuit very near your distro.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 26, 2016, 08:49:56 am
Tim brought it to my attention that the distro suitcase I have is from DimmerRack, and those guys use the P&B mini breakers regularly where space is an issue, or SqD. So lots of distros out there using these on 200A and 400A setups.

As for me, moving away from them, and putting my faith in these now.
QCF1020 (under several names, Cutler-Hammer, Eaton, Westinghouse)
http://www.pacificcoastbreaker.com/Breakers_Original/QCF/

GE THQC 100A double pole
https://hdsupplysolutions.com/1/1/12332-ge-100-amp-double-pole-feed-through-breaker-thqc-2100.html

And of course, after finding all of my SqD distro blocks from all over the place (being shipped now), I land on the DimmerRack site and find a really sweet setup they use for bus bars. 12X12 lexan housing 4 color coded low profile bars with 20 outputs and pass-thru. Would probably fit nicely right at the bottom of my case, so I went ahead and ordered it, cause I think it will be much lower than the SqD blocks. Guess I will resell those blocks if and when the time comes.

In case anyone else needs these including the link. If your distro comes from DimmerRack or AmpShop, odds are you might have your branch wiring shoved under the CAM lug all together, and could use this too. I say might because I think years ago, DimmerRack did not have these bus bars available, or did not use it on smaller more compact setups like mine. Perhaps they used bars on larger case setups.
http://www.dimmerrack.com/blocks.html

Neil

This might be a bit left field, but those breakers have an interrupt capability of 5KA.  I suspect that a 200A cam feed from a nearby transformer might have a prospective short circuit current (PSCC) capability in excess of 5KA if you get a short circuit very near your distro.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: John Daniluk (JD) on January 27, 2016, 03:38:49 pm
I tied a single phase distro into a single phase breaker box with a breaker installed for my service.  After seeing 30A flowing on my neutral, I traced the breaker box back to a 3 phase panel.  The people at the venue had problems with the lighting/audio for years....I wonder why...

If you tie in a single phase to a 3 phase source, keep watch on your neutral.   Also be aware you may unbalance the transformer for the 3 phase and cause some weird problems with the ac.  I have not had problems until over 120a per leg of single phase. 

If the 3 phase is phantom the 3 leg (third leg is transformer derived from single phase) get on the good 2 legs,  lighting people can give more information about this.

jd   
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 27, 2016, 03:47:39 pm
I tied a single phase distro into a single phase breaker box with a breaker installed for my service.  After seeing 30A flowing on my neutral, I traced the breaker box back to a 3 phase panel.  The people at the venue had problems with the lighting/audio for years....I wonder why...

Nearly all commercial buildings are 3-phase, so it's more unusual to not be on a 3-phase feed.  When did you measure 30A on neutral?  If this was while you were pulling a significant load on the two phases you were using, it doesn't seem unusual.  If the load on your distro was unbalanced, you could see 30A even if you were plugged into a true split-phase system.

Significant phase imbalances can be an issue.  Whether a 100A draw on two of the three legs is problematic depends on how large the service is and what else is running.  If it's a 1200A service it's probably not an issue.  If it's a 200A service it could be.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 27, 2016, 04:04:12 pm
So tell me this. My 3-phase service will be 100A (they also have 400A service which is overkill for my needs and distro). Say I tap onto 2 legs (Red/Black), and try my best to balance it out on my distro. I am guessing that first shot, I will be off somewhat, and be unbalanced on both legs. What should I look out for during my setup and testing. My plan after hooking up on both legs was to simply measure the voltage on my individual 16 circuits to ensure I have 110v-120v. I will also have 2 main meters tied into the distro CAMs, each meter between 1 hot and neutral, to measure the incoming voltage on each leg.

My distro consists of 16 Edisons and nothing more.

Assuming the voltage per circuit / leg works out ok on a test meter, what else should be monitored during the show ?? What if the 2 legs become unbalanced for a long period of time, what can that do to the transformer feed knowing blue leg is not being used ??

My understanding is that each leg has 100A available on the feed, and my distro's main will be breakered at 100A as well. Best case  scenario, I look something like this 80A/80A/0A. But worst case scenario, depending on which lights are fired up at a given moment (movers, strobes, smoke), I could look like this 80A/40A/0A.

Then what ??

Thanks
Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 27, 2016, 04:14:04 pm
So tell me this. My 3-phase service will be 100A (they also have 400A service which is overkill for my needs and distro). Say I tap onto 2 legs (Red/Black), and try my best to balance it out on my distro. I am guessing that first shot, I will be off somewhat, and be unbalanced on both legs. What should I look out for during my setup and testing. My plan after hooking up on both legs was to simply measure the voltage on my individual 16 circuits to ensure I have 110v-120v. I will also have 2 main meters tied into the distro CAMs, each meter between 1 hot and neutral, to measure the incoming voltage on each leg.

My distro consists of 16 Edisons and nothing more.

Assuming the voltage per circuit / leg works out ok on a test meter, what else should be monitored during the show ?? What if the 2 legs become unbalanced for a long period of time, what can that do to the transformer feed knowing blue leg is not being used ??

My understanding is that each leg has 100A available on the feed, and my distro's main will be breakered at 100A as well. Best case  scenario, I look something like this 80A/80A/0A. But worst case scenario, depending on which lights are fired up at a given moment (movers, strobes, smoke), I could look like this 80A/40A/0A.

Then what ??

Thanks
Neil
Neil, your company switch may have 100A fuses in it, but you're going to be fed from a much larger transformer.  Don't sweat it.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 27, 2016, 05:51:23 pm
Nearly all commercial buildings are 3-phase, so it's more unusual to not be on a 3-phase feed.  When did you measure 30A on neutral?  If this was while you were pulling a significant load on the two phases you were using, it doesn't seem unusual.  If the load on your distro was unbalanced, you could see 30A even if you were plugged into a true split-phase system.

Significant phase imbalances can be an issue.  Whether a 100A draw on two of the three legs is problematic depends on how large the service is and what else is running.  If it's a 1200A service it's probably not an issue.  If it's a 200A service it could be.

And even more are fed from 3 phase transformers-in fact the entire downtown (OK small town) where I live is fed with 3 phase transformers that in the POCO's terminology are "networked".  Many of the buildings supplied have single phase services or "distro's" in them-our church building actually has both 3 phase and single phase panels.  Doesn't matter where the power comes from the sound systems work fine.

The only time I would see this being a significant issue is IF the "grounds" technically equipment grounding conductors are not separated from the neutrals in subpanels or in distros.  If that is the case, then imbalance will create noise and issues-but that is another topic all together.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Cailen Waddell on January 27, 2016, 08:03:35 pm
I forget if this discussion has covered neutral current.  It is possible - with a single phase distro connected to three phase to overload your neutral.  If you pulled 100a per leg, purely resistive on a single phase distro, your neutral current would be zero.  On a three phase distro, the phases are 120 degrees out of phase.  Thus your neutral current doesn't completely cancel out.  Instead, you would need to do some vector math...  A Google search can get you the formulas.  If I did them right (big if). You could easily have 172a load on your neutral. 

The formula (simplified somewhat)
A=a phase load
B=b phase load
C=c phase load

Formulas are hard on a phone.

Take the square root of
( ( A+.5B-.5C )squared + (.866B -.866C) squared )

So in your case. 100a on A and 100a on B is
 Sq rt of ( (150) squared + (86.6) squared )

Or sq rt of 22500 + 7499

So. Hopefully that translates and gives you additional to think about.


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Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 27, 2016, 10:18:20 pm
First off, kudos for typing all of those formulas and calculations out on your phone, wow, talk about patience.

So according to what you wrote, the issue has more to do with 3-phase distros on a 3-phase panel rather than 1-phase distros on a 3-phase panel, correct? I do get the point, also from a previous poster, that if the 2 legs on a 1-phase distro is not balanced, the neutral can carry the difference/delta. According to your calculations for a 3-phase distro with 100A on each leg, the neutral would have about 173A on it. Interesting. I am trying to understand what you mean by "overload' the neutral. If I have a #2 feeder capable of 190A, and somehow, I manage to throw all this current onto the neutral, wouldn't the feeder cable be able to handle it ?? So where would the overload be ?? And if I balance the 2 legs as much as possible, won't that help alleviate load on the neutral as much as possible ??

Either way, the more I am reading these posts, the more I am happy I invested in a larger feeder wire (#2), which can handle 190A (at the right temp). But I am quite sure if manage to somewhat balance both legs, I should be fine, and if the neutral does carry some current, should be fine as well as I should not reach the max capacity of my #2, at least not with me having a main breaker of 100A on my distro as well as the main panel.

Thanks
Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Mike Sokol on January 27, 2016, 10:47:38 pm
Read this overview on Triplen Harmonics. http://blog.powermonitors.com/blog/understanding-triplen-harmonics

It's relatively easy to generate significant odd-order Triplen harmonics using Triac lightning dimmers or switch mode power supplies on a 3-phase Wye connected system. And the math proves you can generate up to 173% of the line current on the neutral. Many old factories with a lot of 3-phase electric motors would routinely undersize the neutrals to save money on copper. So that's double whammy that can easily cause the neutral wires to burn up.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 28, 2016, 07:09:57 am
Read this overview on Triplen Harmonics. http://blog.powermonitors.com/blog/understanding-triplen-harmonics

It's relatively easy to generate significant odd-order Triplen harmonics using Triac lightning dimmers or switch mode power supplies on a 3-phase Wye connected system. And the math proves you can generate up to 173% of the line current on the neutral. Many old factories with a lot of 3-phase electric motors would routinely undersize the neutrals to save money on copper. So that's double whammy that can easily cause the neutral wires to burn up.
I think we're getting off into the weeds a bit for Neil's usage, but this is another reason why its desirable to run as much gear as you can at 208/240v.  If you aren't using the neutral wire for some things, that part of your load can't contribute to triplen currents.

I did an inventory of my equipment and found that other than dimmers and stage power, I could run almost everything else at 208v/240v, since nearly all my gear has universal power supplies - all my power amps, powered speakers, LED lighting, and movers are good to go. 

The way I am implementing this change is to move to Powercon distribution for a chunk of my cable infrastructure, and then depending on power availability, all I need to change are the input cords - regular Edison to blue Powercon when I am using standard circuits, or L14-20 to blue Powercon wired HHG when I'm using my own distro equipment.  Sticking with L14-20 receptacles means I don't need to do any remote breaker step-downs, and I can still use #12 cabling for everything.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: John Daniluk (JD) on January 28, 2016, 09:01:46 am
There is another interesting thing about 3 phase tie in.  Some locations, older buildings, have a 3 phase with a high leg  ie l-1 120v, l-2 120 v  l-3 220v +- 

I had a hotel give the convention a 3 phase 120v breakout,  the one with the red, blue, black female outlets.  One of the outlets was 220v, magic smoke appeared.   It seems the hotel upgraded the ballroom ac and no one bothered to verify the ac.  I now verify EVERY outlet I use for correct voltage and wiring.
I would advise checking the current on the neutral.   I do this on all single and 3 phase systems. 
There are several good books about working with ac in the production world.
Spend $100.00 and get a volt/amp/ohm meter to use on your shows.  I use a cheap rv volt, wiring checker, simple to use and has an edison m plug, I also carry a standard volt/amp and a rms volt/amp meters.

Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 28, 2016, 12:59:32 pm
I am going to be adding 2 volt/ammeters, and hopefully I can just connect each one to hot plus neutral, and if both sides read 110-120, I am good to go. Then I will meter the individual Edisons as well but they should match what the meters read. I was only going to add coils around the 2 hots for the 2 ammeters, but based on all this feedback about the neutral, might add a 3rd coil around the neutral to monitor it with a 3rd meter.

I know I should not assume, but the hall is quite modern, and not some beat-up thing from decades ago. So I am confident that my metering will show what I am expecting to find and see.

Tom, while you own most of your inventory, and can have 2 sets of Powercon connector cables, not so with me. My LED PARs are pre-wired for 110v, as well as all my DJ stuff (controller, PCs, strobes, smoke, etc), And the rental place where I am getting my MAC250's and bigger sound kit all runs off of 120v, even though I am sure I could ask them for a 220v hook-up, but then it would get messy.

My distro is wired for 110v completely, and all my gear is wired for 110v. I won't be using any lighting dimmers, it's only the movers, couple of Atomics, smoke, LEDs and that is it.

You know, reality is that this hall has all kinds of circuits lining the walls and stage, but I just was lazy and did not feel like running circuits all over this hall in every corner and wall, thought it would be easier to just slap my distro near the DJ table or under the flown truss. Makes for a neater and more controlled run of AC. I sure hope this all works out for me, and that I don't have to worry about the neutral carrying high current, or unbalanced legs, or something funky because I am not using that 3rd leg......

I guess my meters will be my best friend that night....

Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Cailen Waddell on January 28, 2016, 01:25:34 pm
Popping back in here. A single phase distro using two of the three hots on a 3 phase distro can create the 173a of neutral current.   Whether you are using the 3rd phase or not, you are creating an unbalanced load which can overload your neutral...  I would strongly consider an amp meter on the neutral if you will approach capacity and use a 3 phase distro.


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Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Tom Bourke on January 28, 2016, 07:07:40 pm
I know I should not assume, but the hall is quite modern, and not some beat-up thing from decades ago. So I am confident that my metering will show what I am expecting to find and see.
They built a brand new PAC where I use to live.  First show comes in and meters, voltage was WAY high.  Turns out the electrical engineering firm did not know anything about stage power.  They looked at a long life lamp and ordered the transformers tapped at 130 or 135V to match.  I think it was so bad that they had ordered special transformers to hit the wrong voltage!
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 28, 2016, 08:24:57 pm
Hey Cailen,

For argument sakes, let's say that even though I am more or less balanced on both legs of my 1-phase hookup to the 3-phase panel, and I end up with 173A on my neutral, assuming a #2 neutral capable of 190A (ideal temp), where is my worry then ?? My distro should be fine, and so should the 3-ph 100A panel, no ??

Not challenging anything here, just trying to understand where is the worry in this scenario ??

And I think the previous example that got us to 173A on the neutral was me using the full 100A on each leg, which I doubt I will. I think I might be somewhere between 60-70A max per leg.

Thanks !!

They built a brand new PAC where I use to live.  First show comes in and meters, voltage was WAY high.  Turns out the electrical engineering firm did not know anything about stage power.  They looked at a long life lamp and ordered the transformers tapped at 130 or 135V to match.  I think it was so bad that they had ordered special transformers to hit the wrong voltage!
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Cailen Waddell on January 28, 2016, 10:05:30 pm

Hey Cailen,

For argument sakes, let's say that even though I am more or less balanced on both legs of my 1-phase hookup to the 3-phase panel, and I end up with 173A on my neutral, assuming a #2 neutral capable of 190A (ideal temp), where is my worry then ?? My distro should be fine, and so should the 3-ph 100A panel, no ??

Not challenging anything here, just trying to understand where is the worry in this scenario ??

And I think the previous example that got us to 173A on the neutral was me using the full 100A on each leg, which I doubt I will. I think I might be somewhere between 60-70A max per leg.

Thanks !!

It's not a worry - sorry to give that impression.  Something you said earlier made me think you misunderstood the neutral implications.  I wanted to make sure you understood that being balanced on your single phase distro doesn't equal low neutral current on a 3 phase tie in. 

Anyway - I think I may have steered this a bit away from your original objective.   


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Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 31, 2016, 09:55:51 am
While still waiting for all of my distro parts (mostly distro blocks), to beef up my 1-phase distro, in preparation to use it at a big event with 3-phase tie-ins, I came across something interesting on this forum, that I was not aware of. Up until now, most of you are saying that I can somewhat safely tie in my 1-phase distro to a 3-phase panel, so long as I measure and monitor my voltage on both legs, and try to balance the current on both sides. Fine.

BUT, I stumbled across a post on here, that talked about a guy ordering a 3-phase distro from Motion, for use on 1-phase, and that they were using phase conversion to tie the blue leg to the black and red. I am assuming that, if my distro only houses 16 X 20A Edisons, then the "phase conversion" is nothing more than tapping a couple of Edisons off of the Blue leg, to balance out the 16 Edisons across the 3 legs, correct ??

Now, this would change everything for me in my setup, and get more costly of course. My feeder cable is 1-phase, I would have to order another length of #2 SC, as well as Blue Cams. Then, I just ordered a 100A 2-pole main breaker, and am having a custom breaker panel made to house that main as well as 16 QCF breakers. If I were to take advantage of using 3-phase, I would now have to call Jim at AmpShop and hope that it is not too late to change out that main for a 3-pole, probably too late by now, panel already cut and main breaker already purchased. But no harm in asking.

And of course, the final thing is that I really don't need the extra 100A on the Blue leg of the 3-phase feed, I have plenty of juice on the 2 legs. So I would be going thru all this trouble and cost for the sake of balancing things across the legs, and making it look like I am using 3-phase for how it was intended, with all 3 legs.

Thoughts ?? Worth it for peace of mind ??

Thanks
Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: TJ (Tom) Cornish on January 31, 2016, 10:19:44 am
While still waiting for all of my distro parts (mostly distro blocks), to beef up my 1-phase distro, in preparation to use it at a big event with 3-phase tie-ins, I came across something interesting on this forum, that I was not aware of. Up until now, most of you are saying that I can somewhat safely tie in my 1-phase distro to a 3-phase panel, so long as I measure and monitor my voltage on both legs, and try to balance the current on both sides. Fine.

BUT, I stumbled across a post on here, that talked about a guy ordering a 3-phase distro from Motion, for use on 1-phase, and that they were using phase conversion to tie the blue leg to the black and red. I am assuming that, if my distro only houses 16 X 20A Edisons, then the "phase conversion" is nothing more than tapping a couple of Edisons off of the Blue leg, to balance out the 16 Edisons across the 3 legs, correct ??

Now, this would change everything for me in my setup, and get more costly of course. My feeder cable is 1-phase, I would have to order another length of #2 SC, as well as Blue Cams. Then, I just ordered a 100A 2-pole main breaker, and am having a custom breaker panel made to house that main as well as 16 QCF breakers. If I were to take advantage of using 3-phase, I would now have to call Jim at AmpShop and hope that it is not too late to change out that main for a 3-pole, probably too late by now, panel already cut and main breaker already purchased. But no harm in asking.

And of course, the final thing is that I really don't need the extra 100A on the Blue leg of the 3-phase feed, I have plenty of juice on the 2 legs. So I would be going thru all this trouble and cost for the sake of balancing things across the legs, and making it look like I am using 3-phase for how it was intended, with all 3 legs.

Thoughts ?? Worth it for peace of mind ??

Thanks
Neil
What does phase conversion mean?  Short or a rotary phase converter or inverter-based unit, there isn't any way to passively convert single phase to three phase power.

A few distros have a switching mechanism that can be switched so that in "single phase mode" the z phase is split half on each leg. Leprecon makes one like that.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: jason misterka on January 31, 2016, 11:09:14 am
What does phase conversion mean?  Short or a rotary phase converter or inverter-based unit, there isn't any way to passively convert single phase to three phase power.

A few distros have a switching mechanism that can be switched so that in "single phase mode" the z phase is split half on each leg. Leprecon makes one like that.


I believe that is what he is referring to.

In my opinion, as an "audio-only" system provider, there are two reasons to build your systems with three phase or switching PD.

1. You use three phase motors

2. You want to be able to use smaller generators and run them more happily in three phase mode.

If you provide large lighting systems as well and need the current capacity, then certainly go three phase.   Otherwise, you can run some pretty large shows on a 100 amp single phase.

Jason
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: David Buckley on January 31, 2016, 02:56:05 pm
For argument sakes, let's say that even though I am more or less balanced on both legs of my 1-phase hookup to the 3-phase panel, and I end up with 173A on my neutral, assuming a #2 neutral capable of 190A (ideal temp), where is my worry then ?? My distro should be fine, and so should the 3-ph 100A panel, no ??

Well, that's a definite maybe.  In a theatrical space, the neutrals should be 200% rated according to code, so the neutral is rated for 200A, and all will be well.  In some other locations, someone may not have read the relevant chapter in the NEC, or indeed the reason for the cam feed may have been misrepresented to the electrician such that he didn't twig to even look at the chapter, and put in a 100A feed with 100A neutral capability...  Or the supply behind the feed may even have a reduced size neutral.

A 100A distro with 400A cams is fine, as the neutral cam can well take the current.  But this is why bigger distros that have phase loads somewhere near the current capability of a cam have dual neutral cams and use six wire hookups, two neutral cables in parallel.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 31, 2016, 03:46:31 pm

I believe that is what he is referring to.

In my opinion, as an "audio-only" system provider, there are two reasons to build your systems with three phase or switching PD.

1. You use three phase motors

2. You want to be able to use smaller generators and run them more happily in three phase mode.

If you provide large lighting systems as well and need the current capacity, then certainly go three phase.   Otherwise, you can run some pretty large shows on a 100 amp single phase.

Jason

No motors, no generators, just a bunch of powered speakers, movers (MAC 250's), Atomic 3000's, smoke, LED PAR's, stuff like that. I did a quick calculation, and I would be surprised to pull more than 130A-140A total, with everything pulling full tilt, so a 100A distro panel cabled single phase on a 3-phase 100A panel is plenty for me.

And at home, when I run my home haunt, I am on the house panel single phase.

So if I were to invest in an extra run of feeder and CAMS (BLUE), plus change out my main breaker for 3-pole, it's mainly to ensure that everything remains balanced with the 3-phase panel at this event, which will be once a year.

But I think everything will be fine, quite certain I will find 400A CAMS on the 100A panel and expect the internal neutral to be wired accordingly for size. Will stick with my 1-phase 100A setup (breakered in my distro now), and use the 2 legs and done. Especially since there are no dimmers racks, no motors, no generators, and no 208/220/240 gear.

Thanks
Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on January 31, 2016, 11:00:36 pm
One option that would eliminate the need for constant monitoring of neutral current would be to use a 3 pole breaker on a single phase distro.  I don't have my current code book handy, but 2005 allowed an overcurrent device in a grounded conductor (240.22) provided that all ungrounded conductors using that grounded conductor were controlled by the same overcurrent device and that all poles opened simultaneously.

So either size the neutral @ 200% or use a 3 pole breaker and leave the rest of the distro alone-and you should have a safe setup as regardless of your loads/balance.  Balance is still good practice-just not necessary for safety if you have proper safeguards in place.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on January 31, 2016, 11:14:44 pm
One option that would eliminate the need for constant monitoring of neutral current would be to use a 3 pole breaker on a single phase distro.  I don't have my current code book handy, but 2005 allowed an overcurrent device in a grounded conductor (240.22) provided that all ungrounded conductors using that grounded conductor were controlled by the same overcurrent device and that all poles opened simultaneously.

So either size the neutral @ 200% or use a 3 pole breaker and leave the rest of the distro alone-and you should have a safe setup as regardless of your loads/balance.  Balance is still good practice-just not necessary for safety if you have proper safeguards in place.

In my case, with a #2 feeder, my neutral will be capable of 200A (ideal temp), so no worries there. But curious, when you say use a 3-pole breaker (main distro) and leave the rest of the distro alone, what do you mean by that ?? Change my 1-phase CAM panel to a 3-phase CAM panel, then wire the CAMS up to a 3-pole main breaker (100A), and then what ?? Would you use the 3rd hot off the Main to a few circuit breakers/Edisons, or just don't tap the 3rd hot off the 3-pole, using only 2 of the 3 poles ??

Odds are, since I have already invested in a 1-ph CAM and Main Breaker setup, I will probably just stick that way, and rely on a beefed up neutral as suggested, which is what i have. Plus my other usage of this panel will be at home, so 1-ph definitely the way to go in my case.

Thanks
Neil

Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Stephen Swaffer on February 01, 2016, 02:23:56 pm
I should have been clearer.  A 3 pole breaker would let you run each phase conductor through the breaker and leave an additional pole to run the neutral through.  This would allow a neutral overcurrent to trip the breaker.  This is allowable only if it is setup so that all conductors must be opened at the same time.  I did verify that the code has not changed-its even still the same "chapter and verse" in the 2014 code.
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Neil Sakaitis on February 01, 2016, 05:15:02 pm
Hmm, you learn something new everyday. I never knew that one could breaker the neutral, and would be curious to know if any distros out there actually have this setup ? I always assumed 1-ph to double pole, and 3-ph to 3-pole main, and neutral to bus bar and call it a day....

Gonna stick with my 2-pole and neutral on bus, only cause I know my feeder can handle it. But interested to hear back if there is anyone out there with distros setup like this (breakered neutral)...

Neil
Title: Re: (How) Can I connect my single-phase distro to a three-phase tie in?
Post by: Tim McCulloch on February 01, 2016, 07:22:28 pm
Hmm, you learn something new everyday. I never knew that one could breaker the neutral, and would be curious to know if any distros out there actually have this setup ? I always assumed 1-ph to double pole, and 3-ph to 3-pole main, and neutral to bus bar and call it a day....

Gonna stick with my 2-pole and neutral on bus, only cause I know my feeder can handle it. But interested to hear back if there is anyone out there with distros setup like this (breakered neutral)...

Neil

Code generally does not allow a neutral to be protected by a breaker or fuse, but there are exceptions and one of the requirements is that *all* conductors open if the neutral breaker trips.  It's not commonly done and I don't think I've seen it in live entertainment power at the 208/120v level of service.