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[Stephen Swaffer]

Stephen, does the phrase "being supplied by" refer to the main service connection (to the building) to which the 50A split phase distro is connected via the Cali connector?

TJ answered this already-but why should it matter how it is supplied?  In a 3 phase service, phases are separated by 120 deg-not 180 deg as they are in a single phase 120/240 service (think back to high school and vector math).  It is even possible that a building with a 120/240 volt panel is supplied from a 3 phase transformer-my POCO refers to this as a "networked" system.  If I install a single phase service on a networked system, I have to install an additional terminal on the meter base to account for the neutral.

And yes, the NEC is not a design reference-even though that is often how it is used.

[Jeff Bankston]

I called the city of LA again about the non UL listed cable and had a friend in another state do some checking. For non commercial use non UL listed does not matter. Non commercial use would be for home use. My landlord has a spider box with 6/4 that he uses for yard work with the electric mower and tree trimmer and weed wacker. His service is 2 pole single phase. A friend runs gennys on semi trailers and told me long ago that he gets better power results from single phase setting. We always ran the temp gennys in the single phase mode on construction sites and I also use the single phase setting to power the PA. I also use one 6/4 cable from the main distro to one spider box for the PA, I dont daisy chain those.

[Jerome Malsack]

I called the city of LA again about the non UL listed cable and had a friend in another state do some checking. For non commercial use non UL listed does not matter. Non commercial use would be for home use.

 I also use the single phase setting to power the PA.

top line  Non Commercial use  Ok for home.   but when using to power the PA this is commercial use. 

[Frank Koenig]

And yes, the NEC is not a design reference-even though that is often how it is used.

Good point. Complying with code is one thing. Complying with physics is (sometimes) another. I will say though that I find NEC an incredibly thorough, consistent, and sensible set of rules, as rules go. -F

[Rob Spence]

Re: friends don’t let friends use 6-4 on 50a service...

Just because it is a 50amp service doesn’t imply 50a of current draw.

My rig draws around 30a on a bad day. I use 6-4 to reduce the voltage drop.

50a Cali connectors are more common for me than L14-30



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[Dan Mortensen]

I will buy the UL listed. I'm going to continue to use 6/4 for my 25' and 50' runs and 4/4 for the run to my FOH mixer.

Slightly off-topic, but why on earth are you running 4/4 to FOH? Does your mixer pull 50 amps? Is it 1000' from the stage? Do you have massive lights out there?

I can't think of any other reasons to use 4/4 to FOH.

[Tim McCulloch]

We ran 8/5 to FOH  back in Ye Olde Analogue Dayz.  A PM4000 or Midas H3000 could draw 20 amperes.  Steady.  And when the kick drum hit the voltage would drop 5-10 volts.  We needed all the help we could get.

[Chris Hindle]

We ran 8/5 to FOH  back in Ye Olde Analogue Dayz.  A PM4000 or Midas H3000 could draw 20 amperes.  Steady.  And when the kick drum hit the voltage would drop 5-10 volts.  We needed all the help we could get.

Ya, these "Digital Kidz" never had the "fun" of doing good old fashioned rock and Roll, arena style. 6 man lift on the board, 3 TONS of AC feeder....... (well, it sure felt like 3 tons). An occasional X-Fmr for the mains, well, just because.
Ahh. the "Good old days". May they rest in pieces. 
Chris.

[Dan Mortensen]

Ya, these "Digital Kidz" never had the "fun" of doing good old fashioned rock and Roll, arena style. 6 man lift on the board, 3 TONS of AC feeder....... (well, it sure felt like 3 tons). An occasional X-Fmr for the mains, well, just because.
Ahh. the "Good old days". May they rest in pieces. 
Chris.

We ran 8/5 to FOH  back in Ye Olde Analogue Dayz.  A PM4000 or Midas H3000 could draw 20 amperes.  Steady.  And when the kick drum hit the voltage would drop 5-10 volts.  We needed all the help we could get.

In analog console days, for my Series 5/MH4 I had snakes that had 10/4 or 14/4 to FOH, with 180'-200' lengths. At those lengths voltage sag was not a perceptable issue (no lights dimming). I never ran 300'.

None of those, mine nor yours, is 4/4, and Jeff is running that now. AFAIK nobody did it then and since I can't think of a reason to do it now, I'm curious why he feels it's necessary to lug that much copper around.

It is indeed "AC Feeder"; who runs AC Feeder to FOH and why? Unless FOH is vastly more than audio processing.

[TJ (Tom) Cornish]

Re: friends don’t let friends use 6-4 on 50a service...

Just because it is a 50amp service doesn’t imply 50a of current draw.

Code requires all distribution wiring to be sized to the upstream circuit breaker whether that capacity is used or not.  A 1A load from a 50A breaker should be fed by #4 wire (unless you are sure it will never be fed from a 3-phase source where #6 wire is OK per code) as there is the potential for 50A to be drawn in a different circumstance, and small-gauge wire may have too much resistance to trip the breaker if there's a short, but plenty of resistance to create enough heat to start a fire.

My rig draws around 30a on a bad day. I use 6-4 to reduce the voltage drop.

If you're drawing sustained 30A, you are probably spiking a fair bit higher on kick drum hits.  It's not easy to measure this - most volt meters have some smoothing which will read lower than what the actual peak draw was.

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