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Permanent Install

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Tom Bourke:

--- Quote from: Luke Richison on October 09, 2013, 10:09:40 AM ---
* Do we leave the sub panel and run home runs to each element
* Dedicated 60a service instead of sub panel?
* Should we group PA, FOH, and Stage on one larger circuit (20a, 30a?)
--- End quote ---
That is not even CLOSE to enough power to have in reserve.  Admittedly that will cover most normal church productions it leaves you NO room to grow. Here are some reference points:
An Aqua2000 dry ice fogger for  that special Christmas, Rapture, wedding, other big production will eat 2 20A circuits on stage.
That same production may also have a couple of full size moving lights, that's another 20A circuit or two per pair of lights. 
A decent sized amp rack will need two or three legs of 20A to 30A.

Also when sizing an entertainment power system you need to plan for closer to 100% peak power use than a regular house.  During the climax your going to have every light full plus sound rocking.

With out knowing the size of your venue I would want to see a MINIMUM 100A to 200A single phase service for production with plenty of spare room in the breaker panel for expansion or small cams.

As soon as you want to add the option for flying truss it goes to 200A 3 phase minimum. The chain motors will most likely need 3 phase.

Contact a few of the local production companies to come and see your space.  Ask them what power they would need and expect to do a medium to large show in your space.  Then at least prep for that kind of power.  If they want 400A 3phase and you have no intention of ever going that big, at least get an appropriate sized conduit in place so you can pull a feed, put in a camlock disconnect and set a transformer with out breaking into cement to do it.

Edit: Forgot to add that the last theater power upgrade I was in charge of was a 600 seat high-school auditorium.  We had a 400A feed to the main dimming system plus 2 circuits on stage and 2 in the booth that was shared with the "scene shop."  I think we may have had a couple more available in the house.  It was a nightmare.  We would end up running a couple of dimmers in constant on mode to get power for any extras.

We added a 200A 3phase panel with dedicated transformer.  For circuits we added:
8 20A quad boxes near stage floor.
2 L21-20 circuits (3 phase) on 6 connectors in the ceiling for chain motors and breakout stringers for LED's.
7 20A circuits spread threw out the FOH lighting positions for movers and video projectors.
4 circuits in the booth for various needs.
a few more 20A circuits in the scene shop they desperately needed.

It may sound extravagant but ALL our power problems went away!  No more hum from the powered speakers on stage being on a different panel and transformer from the FOH console.  No more rolling ground loop waves in the projectors because now they were all on the same power.  Director wants 2 huge foggers? no problem, I made sure we had 2 locations with plenty of power up stage for foggers.  Flying stuff got much more safe since we could now use chain motors for the heavy lifting.

Something else to watch for if you DO get real power is other places may "need it."  I had the clout to keep them from putting a computer lab on our panel.  You may not be able to keep them from using your panel to also feed the concession stand with a pile of nesco rosters eating 100A.

TJ (Tom) Cornish:

--- Quote from: Mike Sokol on October 10, 2013, 10:56:39 PM ---Agreed.... So while I'm teaching seminars in Texas this week (and not at my desk) I don't have a lot of time to thing about your questions this week. However, I would suggest that to future proof your system you add at least one "house power" connection. In the old days (before LED lights and Class-D power amps) I would have suggested camlocks and a 200-amp circuit breaker. However, I think it's time to revisit a trick I first used some 40 years ago in my misspent youth at the Old Mill Inn. A 50-amp/240-volt Range Outlet (NEMA 14-50) fed by a double-pole 50-amp circuit breaker in the service panel would allow most any medium size act to plug in their own power distro and run quite a large sound and lighting system. Unless you are doing major shows, then 100 or 200-amp camlocks seem like expensive overkill. But a 50-amp/240-volt range outlet located near the stage would give you a lot of future expansion options since that's 100 amperes of 120-volt power which is sufficient for a 10,000 watt PA system and a pretty large LED lighting system. I'll have to double check with my code monkeys, but this should be perfectly code compliant and WAY more legal than letting a visiting band hang some camlock pigtails out of your open circuit panel.

I would appreciate some input from the other sound pro's here. Does this seem like a reasonable distro power idea for a small/medium church or club, or is it too simple/crazy to work? Of course, really big productions need really big power from camlocks, but how much room do you have on stage for potential acts?

--- End quote ---
Mike, in my opinion the 14-50 is a very reasonable choice - still a good chunk of power, and inexpensive components.  Somewhere on one of the forums a few folks mentioned that there were potentially regional restrictions on using a 14-50 for general use and that a CS connector would be more appropriate, but in my region 14-50's are fine, and as you mentioned, infinitely better than panel spelunking.

The other way to go would be a "built-in" distro -  4-6 20A circuits on or near stage that would allow for extra tree-pack dimmers, or whatever.  I believe this is better for the other 51 weeks a year that production isn't brought in - the church wouldn't have to dig out the portable distro just to plug in a couple lights.

I suppose someone with a big amp rack that has a rack pack inside might be loathe to un-patch their amps from the rack pack, meaning a 14-50 would still be desirable, but then it gets to a cost/benefit question, and just how often that would be a problem.

Jerome Malsack:
With some of the larger power amps for items like subs looking at 30 amp  should one consider having one or two 30 amp plugs installed in the amp and at the performance area??

Mike Sokol:

--- Quote from: Jerome Malsack on October 11, 2013, 08:52:32 AM ---With some of the larger power amps for items like subs looking at 30 amp  should one consider having one or two 30 amp plugs installed in the amp and at the performance area??

--- End quote ---
I do have a pair of MacroTech amps at the school with 30-amp connectors so that's a reasonable idea if you regularly roll out the BIG AMPS for certain gigs. However, I really don't like the TT-30 30-amp/12-volt outlet format since it's easily confused with a 30-amp/240-volt dryer outlet. See my NoShockZone article at Now I'm not suggesting you can accidentally plug a TT-30 plug into a an old NEMA 10-30 outlet, but I have dozens of emails from RV owners who paid an electrician to wire up a TT-30 outlet for their 120-volt camper, but found it was miswired with 240-volts since it looks a LOT like a dryer outlet. Of course, plugging your 120-volt RV into an outlet miswired with 240-volts will destroy all the electrical gear in seconds. I still think that every good sound tech should meter all outlets before plugging in any sound gear. 

Luke Richison:
Thanks for all the replies. I really appreciate the advice and knowledge shared. Even though a lot of it seems like overkill for my needs, I enjoy learning the ideal / theoretical applications. I'd really like to learn more about where to place certain elements in the supply chain (sorry if this is detailed in the resources listed in the first reply - I'm still working through them). For example: 200A service >> conditioner / limiter (at FOH?) >> PA mains, or service directly to PA?

Kevin, thanks for those resources. I had stumbled across the Mid-Atlantic paper (probably from the resources section of this forum) but found it a little daunting. I will give it and the others a read. I really appreciate it!

Mike, I really like the idea of pulling that 50A line to the stage. Thanks for the tip!

TJ, thanks for the quick reply. Sorry I couldn't respond sooner. Here's some more specifics about our space and current setup:

* Space (all measurements approximate)
* 250 seats max
* Wedge shaped, 115
* 2500 sqft
* 12' drop ceiling
* seating area (front of stage/PA to back wall)
* 30 feet wide at stage, 85 feet wide at back wall
* 40 feet deep
* stage
* 11 feet wide at back wall, 30 feet wide at front
* 18.5 feet deep
* We will use floor pockets to minimize cords and clutter
* A/V equipment (with specs found in owner's manual)
* 2 Mackie HDA's - power requirements: 100-120 VAC, 50-60Hz, 200W; AC Connector PowerCon A 20A, 250 VAC, Max input 800W
* 1 Mackie HD1501 subwoofer - power requirements: 100-120 VAC, 50-60Hz, 300W; AC connector: 3-pin IEC 250 VAC, 15A male
* Presonus StudioLive 24.4.2 - input voltage range: 90 to 240 VAC, power requirements: 100W
* iMac
* on stage equiment / instruments: no floor monitors or amps
* Video: 1 projector, 2 60-inch monitors
* lighting (not purchased yet)
* Our church subscribes to "less is more" - we won't be doing anything too extravagant with lighting
* House lighting (recessed can lighting) grouped in zones, dimmable
* color wash on stage walls
* front lights (white tungsten, as suggested by TJ)
* This section of the budget would probably be the first to be postponed to a "phase 2"
* We would rather spend the money to have the right power and audio setup, then buy proper lighting gear when more money is available, rather than scrimping on power & audio to make room in the budget for lighting
Thanks for all the advice.


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