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Joined: Mar 2007
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110/208 3Ø Delta is not any system I've ever heard of. Guess I should have double-checked; I meant to write "Wye, NOT Delta"... I have used a Delta service before, but without the high-leg.
Last edited by noderaser; 01/08/09 11:11 PM.
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Joined: Mar 2007
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Your ideas sound good to me... personally I'd even want to lock the 120V outlets, at least if US stage guys are as bad as European ones. I've worked with semiprofessional DJs and the like for a few times, and I always had to keep them from using their 230V extension cords! Each and every single one of them was a different violation! (usually: broken cord caps, poor strain relief, wrong type of cord or even solid wire cable used rather than stranded cord). My absolute favourite: the extension cord with two male cord caps to feed a homebrew light control box (read: wooden box with maybe a dozen switched receptacles, likely not in boxes rated for combustible surfaces). You said it yourself; you worked with "semiprofessional" (Read: Amateur/hack) people... Just like any other industry, there are tons of people who think "It doesn't look too hard, I can do that" without knowing anything about the industry. Bands and church groups are the worst when it comes to this, because they are either volunteer or extremely low-budget. A 1500-seat theatre really isn't that small, especially for a school. Anything less than 200A will probably be inadequate for the occasional "pro" group that comes through. Lighting loads add up pretty quick, when you consider that most stage lights run 500W-1kW+. Most touring dimmer packs (that would use a 3-phase cam feed) come in multiples of 12 2.4kW dimmers, and some are 6kW.
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Joined: May 2005
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My background is technical theatre, and I've been working as a theatrical electrician for ~27 years now.
For a 1500 seat house, I would install at least two company switches, one at 400a, and the other at 200a. I would also provide a sub-panel with a selection of commonly used outlets, something like:
6-9 5-20R (120v 20a parallel blade),
2-3 L5-20R (120v 20a twist-lock),
2-3 L5-30R (120v 30a twist-lock),
2-3 L14-20R (125/250v 20a 1 phase/3 wire grounding twist-lock),
2-3 L14-30R (125/250v 30a 1 phase/3 wire grounding twist-lock),
1-2 L21-20R (120/208v 20a 3 phase/4 wire grounding twist-lock),
1-2 L14-30R (120/208v 30a 3 phase/4 wire grounding twist-lock),
1-2 L14-50R (120/250v 50a 1 phase/3 wire grounding twist-lock).
A lot of this depends on what types of stage stringers, etc, you see coming in the door, what you use in house, and what your local rental houses and a/v companies use. You probably don't need all of them, just the ones that you see regularly, and cover the rest with suitable adapters.
For instance, with the L14-50R, you can use a standard construction type spider box. A lot of the 3-box convention stringers are either L21-20 or L21-30.
I used to work for a major university A/V shop, and we saw or used all of the above on a regular basis.
You can always have a selection of adapters from the various twistlock connectors to the common dryer outlets, etc, or adapters from L21-30 to L14-30, L14-30 to L6-30, etc, to cover special requirements.
One of the nicer company switches that I have worked with was a 200a fused disconnect, fused at 150a, with a hinged cover can mounted below it. The can had oversized double lugs suitable for 4/0 cable, and suitable chase nipples to allow the tails to feed out the bottom. The separate can allowed all connections to be done in a 'cold' enclosure, and the oversized lugs allowed me to walk in with a set of 4/0 tails one easter, when the rental shop was hurting for #4 and #2 tails for the churches.
Another nice touch is indicator lights to indicate when the switch is hot on the load side.
Don't forget to double up the neutral conductor as per the current code, and provide lugs for two sets of tails to each company switch.
If you provide permanent cam-lock type connectors, make sure you either provide both male and female for neutral and ground, or have a couple sets of turnarounds. Even if you provide permanent cam-locks, you still want lugs available.
A local venue has the following (or did when I got the tour shortly after it was built..). It's a large amphitheater with a huge tent.
(4) 400a 3p/4w 120/208 per side for lighting (1600a per side)
(1) 400a 3p/4w 120/208 per side for sound
(1) 200a 3p/4w 120/208 stage right for rigging
(1) 100a 3p/4w 480/277 stage right for lasers (might have been 200a)
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Joined: May 2005
Posts: 247
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Substitute CS6369 type for L14-50R.. The chart shows a L14-50R, but it doesn't actually seem to agree with what is actually available on the market..
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Joined: Mar 2007
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FWIW, our 700+ seat theatre has been open for almost three years, and our 400A company switch has yet to be used. We do get quite a few rentals, but most are community groups and small companies that don't have much (if any) of their own equipment. We provide pretty much all lighting and sound for rentals; the only outside equipment that's ever really been used has been sound gear for a concert. Of course, we have a fairly decent inventory that can cover most of what our renters need, and a professional staff (3 full-time, 1 part) that manages paid students to crew the events.
Our company switch is a 400A model manufactured by Stagecraft Industries, who also did our rigging. It's a pretty rugged, fused enclosure that has a nice big lockable switch on the front with phase indicator lights and spring-loaded covers over the cam connectors. I think the covers may be lockable also. We have two Strand CD-80 supervisor racks in the auditorium and an older CD-80 rack in our black box, for a total of 192 2.4 kW dimmers on the mainstage (minus a few for house lights), and 96 in the black box. IIRC, the feed for the auditorium dimmers is 800A and 400A in the black box.
I have worked at other schools in the area, both secondary and college, and ours is the only one I've seen so far that has a company switch. It is the second-newest. I suspect that most renters who would know what to do with a company switch would probably use some of the non-educational venues in Portland.
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Joined: Aug 2001
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Sorry for the delay in responding.
Many years ago I worked for a guy who did a lot of temp wiring. Expos, tent trade shows etc. Even went to Atlanta Olympics in 96 for him and wired 192 tents. He made power distribution boxes. One may interest you. He took a standard hand truck and mounted a 200 (or 225, I forget which) amp 3 phase 208Y120 Sq D panel on it. For the feed we had 4 4/0 cam locks hanging off it plus the ground cam lock (forgot what size that was). These were about 12" long and we used welding cable. We had many "sets" of 4/0 welding cable with cam locks on the end. We'd go to the nearest panel (hopefully a MDP), capture a breaker (or in the case of our geny we had one already set up for this) and land the cable. In the panel we had an assortment of breakers and on the two sides we had boxes with all sorts of plugs. We carried an assortment of different plugs, breakers and adapters to meet the various situations and rarely found a show we couldn't power up, we simply changed the breakers, plugs etc to meet the needs.
The bad part was the weight of the 200' 4/0 welding cable feeders. You need young guys ... which I'm not.
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Joined: Mar 2007
Posts: 404
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Boxes like you describe are available from the local rental house. I'm all too familiar with the weight of 4/0 cable, and the cost; I had a set of 4 75' 4/0 cam cables stolen from an event site... The thieves left the 12/3 SO and the 2/0 ground cable, and went for the big & heavy stuff. The replacement cost of the cable (not including the connectors) was $4300.
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Posts: 32
Joined: June 2004
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