Powering your systems

[Telecruiser]

How do you get power to your PA? I know on smaller systems the available 120v outlets work. But what about large systems? They take a bunch of power to run efficiently. Do you take right from the incoming power and step it down with a transformer or do you just take from the panel and divide it up with a spider box?

[Mogwix]

It depends on the venue and the available power.

 

Most places I work (small to mid size venues) have 50A service on a range plug. This connects to a motion labs distro that has a bunch of 20A circuits.

 

Other places (larger venues and arenas) have 100A or 200A service on cam locks which feed a larger distro. Some places I need an electrician to tie into the main service panel to power my distros. That or we rent a festival genset.

[BillESC]

There is no one right answer for all venues. For small systems, carrying a couple 100' 12/3SO extension cords will usually allow you to "find" a free circuit.

 

Buying or building a small distro would be the next step. I make this 4 x 15amp distro. It has 15' of cable attached to the breaker panel and I carry with it a 10' bare end tie-in cable and a 75' feeder extension that allows me to use as much or as little cable as required.

 

 

Back when I was touring we carried a 400A 3 phase distro (glad I'm no longer dealing with hundred foot runs of 4 ought.)

[Mogwix]

(glad I'm no longer dealing with hundred foot runs of 4 ought.)

that stuff is really fun when one of your crew runs it backwards

[BillESC]

Been there . . . trying to forget.

[oldschooler]

 

There is no one right answer for all venues. For small systems, carrying a couple 100' 12/3SO extension cords will usually allow you to "find" a free circuit. Buying or building a small distro would be the next step. I make this 4 x 15amp distro. It has 15' of cable attached to the breaker panel and I carry with it a 10' bare end tie-in cable and a 75' feeder extension that allows me to use as much or as little cable as required.

 

 

Is there a reason for not using 20 amp breakers?

[BillESC]

Yes, keeping the distro within code.

 

The tie-in breakers and feeder cable are rated for 30 amp 220v, therefore four 15 amp breakers is the only breaker that can evenly divide the available service for distribution.

[agedhorse]

The code certainly allows larger branch breakers than supply feed breakers provided that the feeder is adequately protected. There is no code reason why those branches couldn't be 20 amp breakers. This is assuming the feeder is 10/3 plus ground and it's protected at 30 amps at the source.

[BillESC]

True, but the 15a breakers were cheaper and there was no need to install a potential for over load since the distro was purpose built.

[Mogwix]

 

The code certainly allows larger branch breakers than supply feed breakers provided that the feeder is adequately protected. There is no code reason why those branches couldn't be 20 amp breakers. This is assuming the feeder is 10/3 plus ground and it's protected at 30 amps at the source.

 

Andy, what's the word on "home made" distros of that sort? I recall you saying something that the distros have to be UL listed as a unit, and you can't circumvent with stipulation that each component is UL listed... but that temporary service panels are fine, as installed by a certified electrician?

 

Bill, that little distro looks awesome.

[agedhorse]

Big 'ol gray area, as a temporary power distro for a construction site it's probably ok as lonmg as it's installed indoors and protected from physical damage and adheres to the code section for temporary power. BUT, it's the issue of portable that makes this so rough, the UL listing of the components that make up Bill's power distro is not for portable applications, it's for installed building use. So, that's where the separate UL listed assemblies for PORTABLE distro come in, they may be for the construction trade (spider boxes) or for the entertainment trade, or the circus/carnival trade, etc. Each application has different requirements, the construction trade generally requires all GFCI protected outlets (other than thru) to comply with OSHA rqts, whereas the portable distros for the entertainment industry generally does not. It's all up to the AHJ as to what will be allowed, and many will allow Bill's and mine with no problems BUT there are exceptions.

 

Here's a small distro that I use, similar to Bill's in all aspects except that mine is higher current and everything is better protected. Also a LOT more expensive. It's hard to see, but it's installed in a 14 space rack, recessed, mounted to a 3/4" plywood insert and the cabling stores in the back and the face is protected. There's 6 x 20 amp duplex and 3 x L14-20R, very handy for small to mid sized audio systems.

[BillESC]

Nice box Andy.

 

I always add the center screw of the duplexes.

[Unalaska]

Freakin' cool. I'm really been under the radar not buying one and only using one if it's supplied to me. I won't use the range plug @ the bar and I'll request a drop at the hotels. All is cool usually, and I do bring extra 50's and 100's to make sure I have enough AC.

 

So how many of you HC users are using a premade distro like the racpac?

[gonzobassman]

I would love to have one.Takes all the "wonder ifs" out of the set-up completely.

[gonzobassman]

Buying or building a small distro would be the next step. I make this 4 x 15amp distro.

 

Do you offer this unit for sale? Checked your web-site but didn't find it.

[Coaster]

i had something happen with my distro last night that i dont understand. 50A distro, 4 prong inlet type deal. 6 20A breakers feeding 4 duplexes and 2 quads. GFCI outlets.

 

bass player (lisenced electrician) went to plug in the distro (nothing plugged into the distro) and got all excited because it arced. pulled out the multimeter and could'nt find anything wrong with the outlet or the distro.

 

plugged the distro in and checked the outlets with the meter and again, ok. didnt arc the second time though.

 

also, both times he plugged it in all the breakers were off.

 

my only idea was static(?) doesnt make a whole lot of sense to me

[dennis a]

 

So how many of you HC users are using a premade distro like the racpac?

 

I assume you are talking about a Motion Labs RacPac. I don't know the current price of one but a few years ago the price of parts to build a similar rack mount distro was about the same as the purchase price of a RacPac. So the answer to the question is yes, we own about a dozen RacPacs and use them for everything.

 

Dennis

[Rezrover]

 

So how many of you HC users are using a premade distro like the racpac?

 

 

Peavey Distro bought used for $300.

[modulusman]

 

Peavey Distro bought used for $300.

 

 

I also have the Peavey Distro. Only need it a few times a year but it comes in handy.

[dboomer]

 

Buying or building a small distro would be the next step. I make this 4 x 15amp distro. Do you offer this unit for sale?

 

 

I doubt it. No one wants the liability that goes with it. Trust me ... it took a year and a half just to get an input cable that the UL boys liked.

[Special J]

We have 5 Motion Labs distros that look something like this:

[Axisplayer]

I use a UL listed CEP spider box (6x20 amp non-GFI and a 220v 30 amp pass thru) with 40 ft of 6/4 with California 50 amp twist locks (male and female ends.) I also carry a 10 ft 6/4 with a 50 amp California twist lock to a 50 amp range plug and a 10 ft 6/4 California plug to bare ends (but I won't install these ends as they are for electricians to tie me in with.)

 

So far I like this setup and it hasn't been scrutinized by inspectors. I am aware that GFI might be better received by some folks. I only use it where I can control the access, and it has a warning stenciled on it "Audio Company Use Only." When I need stage power from it, I have some UL listed GFI extension quad boxes that can feed the stage from my spider box.

 

I bought the spider box for $120 off eBay, the 40 ft feeder with twistlocks off PSW for $100, and bought the supplies to make the two short feeders from my local supply house. I may $300 in everything so far.