This may or may not be the type of thing that I can really get advice on in a forum like this, but I thought I would give it a try. I realize that ultimately, the authority having jurisdiction makes the judgment call, but I don't yet know the local electrical inspectors (and I suspect if I asked them this question with this terminology I'd be seeing more of them, lol). I'm based in BC Canada for what it's worth. Here's my conundrum:
My current distro came from an old install, it was built by an electrician (or so I'm told). I have very little money invested into this thing, and I tried to pick up a Peavey rack mount distro before they were discontinued but.... three times being shipped the wrong product makes even the most patient online shopper give up. I'm at the point where I need to either retire it, or customize it to fit my new strategy, but I'm hoping someone can weigh in on my strategy and tell me if I'm off the deep end. I'll try to use accurate terminology the best I can, but feel free to correct me.
OK, so it's (my distro) simply a 4 x 15a load centre, bolted to a piece of wood (painted black of course) with a handle and some rubber feet. there's a short (3' maybe) nema14-50p pigtail to tie into a suitable receptacle, and this format does seem to be common in the venues I work so I'm happy with that connection type.
Two of the 15a breakers are of the "common-trip" variety, for reasons I can't explain. It uses bx cable (metal jacketed) to run the circuits to a pair of quad receptacles, one circuit per duplex. I changed out one of the duplex receptacles for one that would accept a 20A plug (so I could plug in my Crest Pro-lite 7.5 power amp). I realize this is probably a red flag already, since it's on a 15a breaker, but that's part of what I want to address.
The feeder cable is pretty worn, such that I can't make out much of the writing on the outside of the cable jacket anymore. What I can read, says "30A", so I am not expecting a full 50A of capacity when plugged into a nema14-50R. I don't think that's a wire size issue though, since the breakers would prevent the feeder from drawing any more than 30A. Correct me if I'm already mistaken please.
So, 30A 240v in, to 60A 120v out over four circuits. so far so good (by my logic). there was a brass screw inside, on one of the bus bars that was grounding neutral, which I removed after reading on this forum that neutral should not be bonded to ground anywhere but at the service entrance to the building. Now my ego is flying, so feel free to deflate it.
I have acquired a 3RU rack panel with a 30A 125v locking inlet, and a couple quad boxes on the other side. I installed this in my amp rack for a nice clean "single cable" hook-up to power all my amps. For what it's worth, 30A @ 115v is plenty for my amp rack. For those interested, it seems to be a Hubbell HBL2615 connector (nema L5-30R).
Of course, like anything free, it still requires money spent on it. I have nothing that I can plug that in with, or into, so I thought I could come up with a strategy where I had two power cords built for this amp rack. One would be a Hubbell HBL2613 at one end, and a Hubbell HBL2611 on the other (nema L5-30 R & P respectively), with some 8awg SOOW outdoor rated cable. This would plug into a dedicated L5-30R that I would install on my distro (more on that later).
The second cable would be the same L5-30R on one end, but just a nema5-15P (Edison as you Americans like to call it) on the other for times when I either don't have access to a nema14-50r, or I don't need the amplifier headroom (small venue). seemed like a simple concept, taking advantage of the fact that the input on that rack panel is 115v so i can either give it plenty of juice when available, or a little juice (and get ready to run for those breakers after the kick drum hits!). This way I can leave all of the amps plugged into the same rack panel, and just use the different cords for "small" or "medium" events. less mucking about in the back of a rack on site in the dark, or at least that's the plan.
In order to get myself a 30A 115v receptacle, I thought perhaps I could use the two common-trip breakers, since they seem to be each from a different phase of the 230v power supply and two 15's makes a 30...right? I'm sure there's something here I'm overlooking. The thought was to use the knockout on the opposing end of the box from where the feeder enters, to install a short pigtail with that L5-30R connector on it, wired into those two 15a breakers. then I'd just have each quad box on a dedicated circuit from the remaining two 15a breakers (one per pair of duplex receptacles) to power up backline/lights/fog/FOH/powered delay speakers/catering.... basically anything that's not in the amp rack.
I'm mostly just concerned about this whole common-trip 15a business, and whether that is a suitable replacement to a 30A breaker. I'm going to end up spending a few hundred dollars on adapters and cable to make this work, which makes me think maybe there's a better way with the "right" stuff? Looking for some feedback, or suggestions on other methods to do what I want to do but perhaps better? What have I missed?
Thanks in advance! Here are some pictures: