What I am trying to do is use a transfer panel to power some 15-amp sockets with ether a dimmer pack, or from the main. (trying to set up a theater space so when there's not a show going on you can plug sensitive things into the walls) Can you do this with a transfer panel?

More info: There are 4 sets of 3 outlets (set A, set B, set C). Each set has 2 circuits, and each circuit is rated for 20 amps. (some of the outlets are tied together, it's a bit confusing due to the fact that the space was built in the 40's, how long does it take for the plastic/rubber shell on wires to get go bad?) I want each circuit to be switchable, able to run off the main panel, or run off dimmers that run off the main panel (theses are the big dmx controlled dimmers you would use for theater or djing, they give out 4800 watts @120V spred across 6 channels). Everything would run a at 120V although I can get 240V. Even though its inside a building we get main lines (L1, L2, and a neutral, just like you would get from the street pole), this comes from a sub breaker room, that comes from a transformer, that then finally comes from the street. I'm pretty flexible as in to what the plan is in the end. Sorry if Im just repeating myself, felt that the first Q. was not adequately expanded upon, so I just restated it.

Edit2: Well at least I think its from the 40's but it probably din't go in at that time, there was also some retrofitting in the 80's so any sockets and switches were replaced, the sockets I want to power are ground level, there are no sockets on the ceiling, power goes straight from the light board, through the walls (brick and morder), to "junction boxes" on a grid on the ceiling of the stage. If you can identify the model of the light board I'm planning to take out, that would help me a lot. All I know is that its a Zinsco. And yes, it is used without problems, although it does give out dirty power (have not checked with an oscilloscope, only know by experience). I most likely am going to have to hire an electrician, but I would still like to have a solid plan. Also, as far as I know, and I have searched high and low, any electrical floor plans for the stage do not exist.

This thing also acts as the main panel for half of the building.

A Zinsco light board

  • 2
    If the wiring was done in the 40's the system needs to be rewired. What you want to do should be planned by an electrical engineer and implemented by a licensed electrician. There are many factors to consider to make it safe and code compliant. Remember this is a public place, and liability seems to fall on you. With that said, we can advise you as to what needs to be done if you supply us with more information. You should post a detailed schematic of what is in place now, and a detailed description of what you want to do. – SteveR Mar 8 '12 at 12:42
  • I would recommend against doing things this way for a whole ton of reasons. Usually your plugs are up high because that's where your lights are, otherwise you have cords running all over the place. Depending on the situation, there are also small DMX dimmer packs that can be installed on trusses right beside the lighting (so you run constant power + DMX signal). I would not want to introduce even the possibility of someone plugging some (broken?) piece of electronics in and damaging the dimmer. The regular mains outlets and dimmer-controlled lighting circuits should all be totally separate. – gregmac Mar 8 '12 at 16:15
  • Since you're using dimmers as opposed to newer LED stuff (which many times has its own DMX control built-in), it means you're using stage lighting fixtures are likely 500 to 1000 watts each. I personally would not trust running lighting through old 40's wiring. I used to work on this stuff when I was in high school, and even though the stage was pre-wired (MANY years prior) we just ran our own cords and/or truss-mounted dimmers because the built-in wiring was unreliable: on one occasion a circuit actually shorted out putting on a very nice display of sparks, and we never touched it again. – gregmac Mar 8 '12 at 16:20
  • @ChrisColabella Did you ever end up tackling this project? – BrownRedHawk Oct 16 '15 at 18:23

You can but that takes some work, re-routing wires. I don't know how many breakers you are talking about, but if it's just 2 or 4 you can and you have room in your panel you can use a breaker interlock switch.

Breaker Interlock

The silver bar mounted on the breaker handles does not allow both breakers to be on at the same time.

To answer your question, yes, you can use a transfer switch. But from the picture you can see the advantages of using the interlock. No extra wiring, no subpanel to install. No more breakers to buy. Not many electrical distributors will stock this, and the brand does matter. These usually don't work with breakers / panels from different brands. They are not permanent so they can be removed easily.

EDIT - This is why all information would be great to have. A xfer switch is made to move power from 1 panel to another panel. You can't switch some of the breakers of the panel. So basically the way I see it is that you will need two sub panels, 1 for one task and another for another task. Probably a couple of j-boxes to do some of the wire make-up because some of the wires won't be long enough. Lets say that totals to 30 or 50 amps (just guessing because you have not told anyone that.) Then instead of buying the more expensive xfer switch you can use the interlock, switching the breakers feeding each sub panel.

It really would help if you gave more info, like how many circuits (poles and amps) for one task and the same for the second task.

There are other items you can use for simple things, like breaker handle locks that screw on;

Breaker lock off

or breaker lock outs.

Breaker lock out

Either can be used to lock on or off. The breaker will still trip even when locked. I would prefer the one without the padlock.

You should also check local code to make sure there is no problem having the receptacles out of use, even if it is for part time.

  • With a breaker interlock switch could I use both main power and and my secondary (the dimmer packs) at the same time? (and I would have 6 breakers) – Chris Colabella Mar 8 '12 at 8:03
  • Of course not, that would defeat the purpose. You would need 12 breakers, one to a dimmer and one straight through for each circuit. Also, most breakers are not rated for normal switching duty. They are meant to be operated a few times a year, not a few times a day. You really just need a big double pole, double throw switch. But you still need 2 breakers for each circuit, or smaller switches, one for each circuit. – bcworkz Nov 6 '12 at 20:28

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