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Author Topic: small theater code questions  (Read 3337 times)

Craig Hauber

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small theater code questions
« on: May 24, 2016, 10:41:32 PM »

I am working with some people on fixing up a really-small-town's performance space.  (I mean really small -northern prairie town 2hrs from decent civilization)

I have an electrical contractor who is working on the adjacent school building renovation but they don't know anything about stage and performance space needs -and the relevant codes.  Our local inspector just fails anything he doesn't understand.
Audio is a slam-dunk.  -going to be lots of dedicated 20A circuits in new conduit to a new panel.  GFI's for any performer accessible outlets.  There really wasn't any existing circuits to replace or repair so it will all be new.

The "lighting" is where I'm having issues.
I would like to just run sacopex everywhere (as we've been doing currently) but I know that isn't code for permanent use.  So raceways with numbered outlets on all the A-P's, booms and over stage battens -there is no fly so everything above stage will be just normal surface-mount conduit-and-box on walls and ceiling.
My issue is at the dimmer end of all that.  Currently sacopex just drops down the SR wall and either screws right to the dimmer or goes to fan-outs for patching to dimmers or constant power.
Can you terminate all the conduits in a box/gutter with sacopex panel mount connectors? that you jump to the dimmers either with really short saco cables or fan-outs?
I have seen pig-tail type patchbays but they were ancient and electrician says that probably isn't "legal"
I have no idea what's currently industry acceptable, code acceptable and actually affordable.  (I'm donating, electrician's donating and so are many others -there's just no budget for a "theater lighting architect/consultant" -or a huge architectural dimmer rack.  We use loaners and various 4ch packs as well as LED cans so more-and-more non-dim uses happening.  I have a couple nema 14-60 connectors for powering the CD-80 loaner or my Teatronics rack
So if you know of relevant code sections that cover this, and/or experts I can chat with that I can relay the proper design to my electricians it would be appreciated.

(last time I step outside of my comfortable audio world!  -at least everyone here is so grateful and appreciative)
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Mark Cadwallader

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Re: small theater code questions
« Reply #1 on: May 24, 2016, 11:18:56 PM »

Craig, thanks for helping out on the Hi-Line.  I'm not quite sure that I'm picturing what you have. I think that you are wanting to have a bunch of box-mounted socapex that allows you to use break-ins to mechanically patch to whatever dimmers might be available at a given moment. Is that correct, or have I missed something?

If I understand your code questions (a big if) they are:

1. Can socapex serve as a male panel mount to connect multicore to fixed raceways/boxes?

2. What issues are there in making break-ins to connect non-permanent dimmers (and/or to permanent non-dimmed female recepticles) to the panel mounted socapex?

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Tom Bourke

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Re: small theater code questions
« Reply #2 on: May 24, 2016, 11:32:21 PM »

Given the current trend for LED and such I think I would opt for standard 20A circuits every few feet in strategic locations.  Then a chase way to your central dimmer area for temporary SACO.  If you want to get really fancy add an ETC smart pack or similar 12 CH 1.2K dimmer at strategic locations.

The last theater I upgraded was a 600 seat high school auditorium with no fly system.  Existing system was a mostly full Strand 96 space CD80 Dimmer rack covering stage and house lights plus 1/2 dozen outlets from a couple of electrical rooms.

I requested and got a 225A 3 phase 120/208 panel.  This supplied 4 circuits in the booth, 4 circuits in the shop area, 6 circuits at stage level, 7 circuits at FOH cove, and 3 21-20 on the stage ceiling. The 21-20 were intended to supply LEDs and movers as well as chain motors.  We also got some 21-20 band stringers.  They ended up attached to the battens to power LEDs.

Over all the system worked as intended.  The 21-20s are used for motors at times and the rest of the time they work great for all the LED's  The 7 circuits at the FOH cove work really well.

From this experience and your description I would push for lots of "normal" circuits your AHJ can understand as well as some well defined cable paths for "other" needs. 
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David Buckley

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Re: small theater code questions
« Reply #3 on: May 25, 2016, 12:18:51 AM »

I would like to just run sacopex everywhere (as we've been doing currently) but I know that isn't code for permanent use.

Its time for an anecdote.  The play "The Mousetrap" ran for many decades in London at the same theatre, and after about 30 years, an inspector queried the fact that the lighting was all set up to "temporary" standards (ie long cords, lamps on bars with clamps) and it had been this way for, well, about 30 years, and that the time had come to stop calling this a temporary installation.

The production were given two choices, either (1) make the whole thing permanent, or (2) dismantle the rig every six months, inspect it while its on the floor, and then put it up again.

Needless to say, they chose option 2.

So this leads to the question of what is permanent?  In a theater that doesn't have the same show playing for ever, then everything changes all the time.  No two shows have the exact same light rig, and thus the socas will be moved around as necessary and replugged to suit the show.  So it's not really a permanent installation, is it?
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Jean-Pierre Coetzee

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Re: small theater code questions
« Reply #4 on: May 25, 2016, 03:16:10 AM »

EDIT:

See my previous message was broken.

In the first topic in this subforum is a white paper,  actually 2 but use the second one, on grounding for entertainment systems. I'd say print that out for your contractor and have him read it with regards to your audio power needs.

I cannot comment on the lighting though, sorry.

http://media.wix.com/ugd//ceae4b_8c0c4a9b4123ffab3138af4b32a6f483.pdf

This is the link to that white paper
« Last Edit: May 25, 2016, 10:06:29 AM by Jean-Pierre Coetzee »
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Cailen Waddell

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Re: small theater code questions
« Reply #5 on: May 25, 2016, 07:33:43 AM »

I can't quote code, but it is common practice and acceptable to have dry circuits that go to a multi pin disconnect panel where they are parched into dimmers.  It's still being done in large road houses to allow touring shows to pickup FOH lighting on their dimmers.  I also know several theaters that have had this done for other various reasons...

I don't see why you should go to hard raceways unless the $$ is there.  Inspect every 6 months. 

The local Barbizon lighting office can probably help you on this in terms of quoting code, they will want to give you a quote on selling you the junction box with the 19 pin tails, but let them, you will need to buy one anyway, so it is UL listed.  You need to buy all the distribution from somewhere really...

Also Everything must get its own neutral, don't care if code says you don't need it, you do, due to uneven loads and distortion of the sine wave from dimming


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Craig Hauber

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Re: small theater code questions
« Reply #6 on: May 25, 2016, 11:02:57 AM »

Craig, thanks for helping out on the Hi-Line.  I'm not quite sure that I'm picturing what you have. I think that you are wanting to have a bunch of box-mounted socapex that allows you to use break-ins to mechanically patch to whatever dimmers might be available at a given moment. Is that correct, or have I missed something?

If I understand your code questions (a big if) they are:

1. Can socapex serve as a male panel mount to connect multicore to fixed raceways/boxes?
Yes that's basically it.
I like the idea, from another reply, of just putting normal power everywhere and just using DMX fixtures or local dimming -and if that's the way it has to be then so it will be,
but I've seen many patch systems in my travels and was wondering what the code was for those or are they all grandfathered?  I'm not referring to single-wire hotpatch setups within large dimmer cabinets (by ETC or similar) but actual building wiring built by electricians from standard nema supply-house parts. 
We still have many conventionals and probably will get more as they tend to be donated more frequently nowadays (like analog audio gear) -that and my dimmers don't fly well
Quote
2. What issues are there in making break-ins to connect non-permanent dimmers (and/or to permanent non-dimmed female recepticles) to the panel mounted socapex?

Yes, -but obviously that stuff would not be connected and deployed for the inspection, and they obviously don't ever get followup inspections or their existing system would have been condemned 30 years ago!
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Craig Hauber
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Jonathan Johnson

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Re: small theater code questions
« Reply #7 on: May 25, 2016, 11:10:56 AM »

Also Everything must get its own neutral, don't care if code says you don't need it, you do, due to uneven loads and distortion of the sine wave from dimming

To put this in terms your electricians will understand, there should be NO multiwire branch circuits. That is, no shared neutral.

It's common practice to save money and time by using a single neutral conductor with two (or three) "hot" circuits that are on different poles (or phases). With resistive loads, this isn't a problem. With single-phase service, it *might not* be a problem. With three phase circuits and switched-mode power supplies, you can end up overloading the neutral wire.

Refer to this thread: http://forums.prosoundweb.com/index.php/topic,152188.msg1395726.html#msg1395726

So no shared neutrals. Every single-pole circuit MUST have a dedicated neutral back to the service panel. For the panel servicing the lighting system, the electricians may even need to upsize the neutral to LARGER than the phase conductors.

I'm just an armchair engineer, so don't take the above as proper engineering. I'm just pointing out some things to be aware of.
« Last Edit: May 26, 2016, 01:24:50 AM by Jonathan Johnson »
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David Buckley

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Re: small theater code questions
« Reply #8 on: May 25, 2016, 08:43:08 PM »

For the panel servicing the lighting system, the electricians may even need to upsize the neutral to LARGER than the phase conductors.
There is a chunk of the NEC that specifically refers to theatrical installations, and this is in there, assuming the state has adopted the relevant section of the NEC.  Perhaps many electricians never got as far in as 520-53(O).
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Re: small theater code questions
« Reply #8 on: May 25, 2016, 08:43:08 PM »


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