I work for a pretty big school district. We have a theater that we rent out to other groups for concerts, plays, etc. We get a few groups in each year, mostly concerts, that have specific electrical needs and we end up running temporary power for concerts. They usually need 120V or 208V circuits, sometimes single and sometimes 3 phase at anywhere from 20 to 60 amps. And they sometimes need multiple circuits with different requirements.

The roadies show up a few hours before the band and start setting up the stage. All of their equipment has long cables with bare pigtails that they want to tie in somewhere. Fortunately we've got an electrical distribution room only 50' away from one of the stage wing doors and we've been able to pull their cables to there and provide what we need.

I'd like to put something on the stage so we can tie in right there. I picture a sub-panel with several breakers, providing both single phase and three phase branch circuits at several different amperages. Each branch circuit would feed a junction box next to the panel where we could do the tie in.

I don't want to re-invent the wheel. Is there anything like this that's standard in theaters? And if I go with my idea, what's the best device to install to tie pigtails into. I picture something with lugs that we can just insert the wire into and tighten down the screw. I've also considered individual fusible disconnects. We could tie the band into the bottom lugs and then put in the appropriate fuses. But I can see the bands wanting 100A on #10 wire and swapping fuses after we leave. The cables the bands provide are anything from #8 to #2.

Two months ago, I got a call on a Saturday afternoon that a concert was starting at 6:00 and the band had no electric. There was a contract mix up between the band, promoters, and us and we didn't know they needed several dedicated lines. By the time I got there, a 20 year old shaggy haired kid had the cover off of one of our 480V panels and was about to tie his 208V equipment into the panel's main lugs, hot, "like he always does". Fortunately our theater manager caught him and stopped him before he killed himself and the rest of the band. So I want this to be as simple, straightforward, obvious, and idiot proof as possible.

Thanks.

"So I want this to be as simple, straightforward, obvious, and idiot proof as possible."


When you make something "idiot proof" they just make bigger idiots.

I don't know about a standard but I'm thinking receptacles each labled as to voltage, amps and phases.

What would serve you well is what is known in the theater trade as a "company switch". It's a fused disconnecting means that can be fitted with gigantic receptacles on the outside of the enclosure so shaggy doesn't even need to open the door. They are available in various voltages and amperages. Several companies make these, but Union Connector is probably the biggest.

http://www.unionconnector.com/cswitch/index.htm

Maintenanceguy:
First and foremost consideration for any band/house/etc source of power is....a responsible person/qualified person on-site when any terminations are made. No, not after the fact, but from the moment the 'boys' walk in.

For the country clubs that I worked at, we had a 200 amp, 120/208 3 phase 'band' panel for the ballroom stage, a 200 amp locked disconnect ahead of the panel, and had 1 electrician on site for connect/disconnect. The same type setup was outside near the pool/patio areas.

Granted....it cost $$$ to have a qualified electrician 'on site' for +/- 8 hrs.....but it's cheaper then legal issues here in the lawyer capital!

BTW, a good solution to keep the shaggy hairs, and bald guys out of the panels is a hasp/padlock from backbox to cover...play with the cover screws all you want boys!!!

Installing various voltage/amperage/phase recepts proved to be a waste; no matching male caps owned by the 'boys'.

200A 110/208 3-phase delta company switch should do the trick, and plenty of 20A 110V outlets around... Cam-Loc is the standard for dimmers and distro boxes, and adapters are available at any self-respecting rental house for the odd equipment that uses something different. The sqweeks will also want, at the very least, to have their equipment on dedicated circuits, if not on dedicated circuits with ground isolated from the rest of the building. They're frequently labeled with blue outlets.

110/208 3Ø Delta is not any system I've ever heard of.

A delta system would certainly discourage the "roadies" from making connections on their own. .... after they burn up some amplifiers and lighting on the high "B" leg.

The standard distro for road shows is a 400 amp fed by single conductor cables and cam lock connections.
This is probably overkill for a small theatre and 200 amp switch with cam locks is probably enough. Have fuse adaptors for 100 and 60 amps for the 200 amp switch. A couple of range outlets covers the other little guys and bands. Almost any community hall has a stove and garage bands tend to buy a domestic range cord and splice it on to a length of cab-tire. I know that when I see the range cord spliced on that the band will be off to the wholesale to buy a fully rated 50 amp 120/250 volt plug to ensure the full size neutral. They always whine that the plug is $60.00 and the range cord is only $10.00
As suggested a couple of outlet enclosures on either side of the stage with some 20 amp t slots maybe a range outlet and a dryer outlet too. It is good to have every source of power locked so the band has to consult with a qualified person at the theatre
Tamper proof screws on cabinets or double screws with wire seals. Always ensure there is a qualified person under the employ of the theatre to ensure what ever is connected does not damage the house wiring or allow poorly maintained equipment to be connected. If there is an Audio company in town that rents show equipment it can be a show saver to know their 24 hour numbers in case there needs to be a last minute rental. Also you can better tailor your stage power by knowing what is out there in the local community.
The biggest power demand we have ever had at our 8000 seat arena was 4 X 400 amp show distributions for Tool. One 400 amp was just for the laser.

Thanks everybody.

Looking at the company switch specs, it seems to be overkill for our little 1500 seat theater but I like the cam lock connectors. I now thinking about installing a 200A 120/208V subpanel with one 100A and two 50A breakers. Each breaker will feed its own set(4 wire + ground) of pigtails with cam lock connectors on the ends. The pigtails and attached cam lock connectors will be inside a large enclosure box with a hinged, and padlocked cover. We'll provide (groups must sign for and return) the other half of the cam locks if needed.

If I'm feeling especially creative, I might even install the pigtails so they can't reach beyond the enclosure and have a shunt trip breaker that opens if the enclosure door is opened so it's impossible to get access to the pigtails unless they're closed up and safely tucked away from being touched. That also prevents plugging or unplugging anything hot.

You'd have to open the box, make your connections, close the box, and then turn on power.

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).

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.

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.

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)

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..

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.

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.

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.