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.
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.
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.
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.
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).