Single and Three Phase power conection questions?

M

Matt Vivlamore

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Jan 11, 2011
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Help me learn and educate myself on Power for Event Production; aka what can I and can’t I do? I had a “situation” arise this weekend at the venue. The Party/Tent rental company provided a 45kW generator (WhisperWatt) for the event and they provided a Power Distro as well. The generator was set-up to run the provided Power Distro on 3-Phase 208/120 Volt because the Catering Company needed to use an L21-30 plug for one of their warmers/cookers. Originally it was planned for me to pull power off the 50-Amp Cali Plug; HOWEVER it only functions when the Single Phase switch is selected. Anyways, I ended up tagging off the main PD with 4 Extension Cords and the event happened without any problems.

By the end of this year I want to be versatile with power and be able to connect almost anything out there. I have a good understanding of Single Phase in 120 and 240.

I am confused 3 Phase power and this is where I need help, but I do know that if the 3-Phase is 208 there are 3 hot legs of 120v with a Neutral and Ground.

So to start the questions…
If I go into a Venue or on a Generator with 5 tails pushing out 3-phase 208 (because it meters 120v across a Hot and the Neutral). Can I connect to the Red, Black, White & Green and power my single phase distro?

If it is 277/480 – 3 Phase; how is it possible to drop it down to a usable 120v? Or should I just avoid this at all cost.
 
Re: Single and Three Phase power conection questions?

Matt Vivlamore said:
Help me learn and educate myself on Power for Event Production; aka what can I and can’t I do? I had a “situation” arise this weekend at the venue. The Party/Tent rental company provided a 45kW generator (WhisperWatt) for the event and they provided a Power Distro as well. The generator was set-up to run the provided Power Distro on 3-Phase 208/120 Volt because the Catering Company needed to use an L21-30 plug for one of their warmers/cookers. Originally it was planned for me to pull power off the 50-Amp Cali Plug; HOWEVER it only functions when the Single Phase switch is selected. Anyways, I ended up tagging off the main PD with 4 Extension Cords and the event happened without any problems.

By the end of this year I want to be versatile with power and be able to connect almost anything out there. I have a good understanding of Single Phase in 120 and 240.

I am confused 3 Phase power and this is where I need help, but I do know that if the 3-Phase is 208 there are 3 hot legs of 120v with a Neutral and Ground.

So to start the questions…
If I go into a Venue or on a Generator with 5 tails pushing out 3-phase 208 (because it meters 120v across a Hot and the Neutral). Can I connect to the Red, Black, White & Green and power my single phase distro?

If it is 277/480 – 3 Phase; how is it possible to drop it down to a usable 120v? Or should I just avoid this at all cost.
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277/480 should not be an issue you run into unless you're in a factory. Don't worry about it. You can rent transformers, but again, that's going to require an electrician, probably permits, and a lot of hassle. I do not foresee you ever running into that voltage.

Hooking up a single phase distro to a 3 phase source is not a problem. Just don't use the last hot leg.

The generator has a limitation that shuts off the single phase outputs when you use it in 3 phase mode. You should have a set of cam Ts and be set up to split off the output to your own distro, or provide the main distro that can cam-out to the other distro.
 
Re: Single and Three Phase power conection questions?

Matt Vivlamore said:
What is the cable code for single wire "feeder" cable?
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Not sure what you mean here.

If you need to adapt cams to california, I recommend a breaker enclosure with a 50-amp 2-pole breaker. Run the cams in one end (either tails or panel mount), mount the California in the other. Super cheap and easy option. Paint it black if you're really concerned about looks.
 
Re: Single and Three Phase power conection questions?

Matt Vivlamore said:
What is the cable code for single wire "feeder" cable?

I can't peal the shell off my 4/4 SEOOW and use that as bare tails, the inner jacket doesn't hold the cable rating as well.
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IIRC the minimum AWG for single conductor feeder is #2. It's a Code thing. Ah, found it in my 2005 NEC - 520.53(H)(2) "Single-Conductor Cables. Single-conductor portable supply cable sets shall not be smaller than 2 AWG conductors. The equipment grounding conductor shall not be smaller than 6 AWG conductor." You need to read beginning with Section IV,"Portable Switchboards on Stage" from Article 520.50 . Stop reading when they get to Dressing Rooms. You'll learn some lampie stuff, sorry... ;)

Then get thee hither to Article 525. Read it all, it's short. Then on to 640. In all of the Articles you'll be referred to things in 200 and 300, and some 400. You'll need to read them and glean what is applicable to us. Also note that 520 and 525 have additional requirements to (or a few exceptions to) what is in 200/300/400.

Then sit back and think about it all. The meat is in 520.53.
 
Re: Single and Three Phase power conection questions?

Matt, i have the NEC book if you need to borrow it.

All I can remember ever seeing in practice is single conductors from cams into some distro device.
 
Re: Single and Three Phase power conection questions?

Probably so, but there have been some changes to the "Special Occupancies" in Chapter 5 and "Special Equipment" in Chapter 6 since the 2005 Code was released.

Local governments do not usually adopt the most recent Code immediately, some are probably still at 2003, many are at 2008.

Also note that it's up to individual states and municipalities to adopt whatever part of the Code they see fit; sometimes it's everything, sometimes parts are excluded (arc flash interrupters are excluded in Wichita because the builders assn claimed they would raise the price of new homes, so the city council chose to not adopt them), and some places have more stringent Code (Los Angeles, among them). When in doubt, call your local Authority Having Jurisdiction and ask which version of the Code is most prevalent.
 
Re: Single and Three Phase power conection questions?

Ok so looking at my Picture A is incorrect by NEC 520.53(H)(2). But I can use the cable Picture B and tie into the Generator Lugs and/or a Breaker panel (with circuit breaker on the hots).


You can purchase Type SC in a variety of sizes: 8, 6, 4, 2, 1, 1/0, 2/0, 3/0 & 4/0.
 

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Re: Single and Three Phase power conection questions?

Tim McCulloch said:
IIRC the minimum AWG for single conductor feeder is #2. Portable supply cable sets shall not be smaller than 2 AWG conductors. The equipment grounding conductor shall not be smaller than 6 AWG conductor."
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Your drawing is a bit off to my interpretation of the code Matt.... What Tim quoted is that the 2 power conductors AND the neutral have to be 2AWG MINIMUM on PPC (portable Power Cable)... only the ground leg CAN be as small as #6....
so
#2AWG - Black
#2AWG - Red
#2AWG - White
#6AWG - Green

This would bring your cable to a 150 amp rating (at least in Canada) bundled, NOT bundled I think carries it close to 180 AMPS...

Feeder is a buy once cry once thing, believe me I'm about to cry again....
 
Re: Single and Three Phase power conection questions?

Matt Vivlamore said:
Ok so looking at my Picture A is incorrect by NEC 520.53(H)(2). But I can use the cable Picture B and tie into the Generator Lugs and/or a Breaker panel (with circuit breaker on the hots).


You can purchase Type SC in a variety of sizes: 8, 6, 4, 2, 1, 1/0, 2/0, 3/0 & 4/0.
Click to expand...

The 2008 NEC had lots of changes. I know it costs more, but buy the "workbook" as it has explanations to the "code".

If I remember right (and I am sure Tim will correct me here), cams MUST be single conductors and CS connectors must be multi conductors so you can't have a CS on one end and Cams on the other?

So, what was suggested is an adapter box (I think I may make one too) with Cams in and a CS out and with a proper breaker.

Ok, so now I have a question... I believe there are different types of Cam Like connectors? Mini-cams and perhaps big amperage cams??
Educate me please?
 
Re: Single and Three Phase power conection questions?

Rob Spence said:
The 2008 NEC had lots of changes. I know it costs more, but buy the "workbook" as it has explanations to the "code".

If I remember right (and I am sure Tim will correct me here), cams MUST be single conductors and CS connectors must be multi conductors so you can't have a CS on one end and Cams on the other?

So, what was suggested is an adapter box (I think I may make one too) with Cams in and a CS out and with a proper breaker.

Ok, so now I have a question... I believe there are different types of Cam Like connectors? Mini-cams and perhaps big amperage cams??
Educate me please?
Click to expand...

Series 16 are the normal cams. The only ones you should see.
 
Re: Single and Three Phase power conection questions?

Silas Pradetto said:
Series 16 are the normal cams. The only ones you should see.
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+1. There are a bunch of versions of 16 series for different wire sizes, but they will all mate with each other. The other stuff is oddball and should be avoided unless you have a really good reason.
 
Re: Single and Three Phase power conection questions?

Rob Spence said:
Thanks.

Are there different brands or preferred ones? I have much to learn here.
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Not sure if there is any material difference between brands. The biggest gotcha is that some implementations have reverse gender neutral and ground conductors, theoretically designed to reduce the chance of connecting things wrong. I'm not sure if it actually helps or not.

Always connect in this order: Ground, neutral, phase 1, 2, 3. Disconnect in the reverse. Meter EVERYTHING.
 
Re: Single and Three Phase power conection questions?

TJ Cornish said:
Not sure if there is any material difference between brands. The biggest gotcha is that some implementations have reverse gender neutral and ground conductors, theoretically designed to reduce the chance of connecting things wrong. I'm not sure if it actually helps or not..
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If someone plugs in ground or neutral to any of the other legs, they are retarded and deserve to be fried... :)
 
Re: Single and Three Phase power conection questions?

Shane Presley said:
If someone plugs in ground or neutral to any of the other legs, they are retarded and deserve to be fried... :)
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The problem is the person doing the "plugging in" is usually not the one who gets fried. It's usually the guys on the other end and/or their gear.
 
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