Theatre Company Tie

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lile001

lile001

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I am working with a theatre, not a movie house, but a real stage. Currently they have a 400 amp 208 volt breaker labeled "Company Tie" that the theatre director says a traveling company may use to power whatever. THis may be for their amps in a big rock concert or for special lights, no telling. We are replacing the entire electrical service as part of a major renovation.

In the specs for some theatres, I see listed several 208 volt 3 phase breakers available for "company tie" - sometimes a half dozen 400 amp breakers! But no indication of how the companies actually connect.

THere are some plugs on the side of the switchgear, that resemble giant sized bananna plugs, near the Company Tie breaker. Two black grounds, a white neutral and three colored phases. Nobody knows what these are for, the GE rep says they are a field addition to the electrical switchgear.

How do traveling theatre companies and rock concert shows tie in to the house electrical system? Is there a special connector that is standardized? do they just open up the panel and tag onto a spare 400 amp 3 phase breaker? Does it vary from house to house?

--Lawrence Lile, P.E.
 
Re: Theatre Company Tie

I have tied in traveling shows quite a few times.

One way is through the use of "Cam-Locks" (the bananas)

Or the traveling show hands the venue electrician (me at the time) a set of leads to connect directly to the feed, in my case we used fused disconnects in place of breakers.

If you are sizing feeders count any feed that will power amplifiers as a non-linear load.

The medium size rock shows I hooked up needed 200 amp 3 phase 208/120 for sound and 400 amp for lights.

The larger ones I hooked up needed 400 amps 208/120 3 phase for sound and 800 amps for lights.

They also often need an additional 100 amps for winches.
 
Re: Theatre Company Tie

Aha! The product is "Cam-Lok" by cooper crouse hinds. They make a 300 and 400 amp version, and some NEMA 3R covers. The basic connector is not finger-safe, without the NEMA 3R connector.

--Lawrence Lile
 
Re: Theatre Company Tie

So I understand that the lighting above the stage is usually hung from 1-1/2" steel pipe, called a grid or a gridiron. Apparently this pipe can be raised and lowered. This makes me immediately wonder how the power is hooked up to each light?

I find some products made by Altman which are essentially big sheetmetal boxes with a lot of knockouts, painted flat black, which are used for electrical distribution to these pipe-mounted light systems. Do stage electricians prefer twist-lock connectors?

--Lawrence
 
Re: Theatre Company Tie

I think I can contribute some to this thread, I used to work for a sound company.

Many theaters have a "road switch". most of them are safety switches, some have camlocks on the bottom, the ones that don't are meant to tie in to "tails", ie raw wire. A tour will typically have a tails to cams adapter to get things to camlock for the rest of their distribution. Usually there is a house electrician that does the actual tie in, with the road crew measuring voltages to make sure all is well before they connect the electronics. Nothing is standardized here, usually some house to road crew interaction is needed, many houses have a "tech rider", which is a sort of bulletin outlining their tech capabilities.

The banana plugs are indeed camplocks, they are made by a variety of manufactures, I know Leviton is another brand in addition to the ones above. Also, I have used 100 A, 200A and 400A camplocks, depends on the size of things. Here are some "distros" that are made by a company in new york, these are typical things on medium to large shows. A distro would be equivilant to a switchboard or panelboard, though tap rules are often times stretched here!

Other power distribution items: you can get 2-fers etc for camlocks, let you go all over the place. Neutral and ground are USUALLY reversed compared to the Hots. Ie: if all the hots on a panel are males, the N and G will be females. This prevents very bad accidents, as many times the camlocks are connected HOT. OSHA is not prevalent in the entertainment industry, and machoism runs rampant

For lighting: Twistlock is out in a big way. They don't hold up to the constant re-patching that goes on. I have seen them melt, spark,etc. Stage lighting is 400-600W per fixture, it's easy to fully load a circuit. For individual fixtures, a plug called stage pin is used. Picture of a 20A plug , they also come in 60A and 100A (for BIG lights, not that common.) For touring rigs, pieces of Truss with the lights mounted inside of them (PAR BARS) need to be quickly connected to a dimmer rack. . For this, a SOCAPEX connector is used, it's 19 pins, so you get 6 channels of light on it, depending on how you wire it up.SOCAPEX INFO The dimmer rack will have a bunch of socapex connectors on it, labeled 1-6, 7-12, etc. You connect a cable from the rack up to your par bar, which will have an adaptor that takes you from socapex out to stage pin, and to your fixtures.

Now, permanent instalations: A theater will have pipe battens (1.5 or 2" Sch 80 pipe, or truss), above the stage, these are typically called the "electrics", and numbered 1st elect, 2nd elect, etc. Anyways, they do indeed have to be raised and lowered to change lamps, refocus, etc. Power is typically run up to the top of the theater, and then transitions in a large splice box (usually with a row of terminals, ala industrial control cabinets) to a huge flexible cable (think of 12/3 SO cord, but a lot bigger) Extensive use of Kellems grips, as well as a counterbalance that pulls the extra cable up when you raise the bar. Well, the other end of the cable goes to the pipe, and you can go a lot of ways here, hanging tails, or my favorite, connector strips, with optional DMX512 plugs, for controls.

Wow, that was longer than expected, that's theater electrical in a nutshell, however it goes deeper than that. Usually there is a theater consultant onboard with large theater projects to clear up a lot of this stuff, it's not the usual electrical we deal with.

Any other questions or comments, please ask,
Mike Hulbert
 
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