115 volt AC to 220 volt AC

[TimMiller]

Re: Pulling 240v from two 120v circuits

If you are going to run 240/208 at least use a rated connector. Most movers can run on 120 check with the shop and see if they can be ran on 120 and they will typically swap the connectors and voltage for you. I was always happy to do this as a free service to prevent and strange wiring just like I would loan out non dim modules. I wanted to protect my equipment and help prevent any liabilities. If you have 120 and need 240 the best way is by using a transformer. They are the most safest and easiest way of fixing this problem besides changing the voltage taps on the fixture if 240 is not avaliable.

 

[danTt]

Re: Pulling 240v from two 120v circuits

I'm lighting a small corporate event in an office building, and I have a few Mac 575s I was hoping to use. They run on 200-240v, but there aren't any accessible 240v circuits in the building. I was talking to the building electrician, however, and he told me it would be possible to pull from the hots of two normal 20a 120v circuits, make an adaptor, and wind up with 208/240v. I've heard of things like this, and it makes sense to me in theory, but seems incredibly sketchy. Is this safe, and if so, how would I go about doing this?

My first instinct would be to do something like wire up a twofer in reverse with two male edisons to plug into the 120v wall circuits, and a female L6-20 on the other end, but that just seems like a bad idea. In my experience, jury-rigged solutions like this rarely end up working well, so I'm wondering if this is a more common practice than I'm aware, or if this building electrician happens to be an idiot.

It also doesn't seem like it can be that simple. Would drawing from two 20a 120v circuits give you 40 amps of 120v, or 20 amps of 240v? Would a transformer of some kind be needed to step up the voltage?

You should have the building electrician install a service capable of powering these. Whether it's a disconnect of some sort that you can connect your own 208v PD to, or simply an L6-20 plug or two in a helpful location is up to you (Actually, an L21-30 plug might make the most sense, and then you can use a variety of breakouts to get the power you need. The fact that the Building Electrician suggested the solution he did scares the poop out of me, honestly. And he's a licencensed electrician? If that is the solution he gives you, make sure he does all of the power connections, and you go nowhere near any of it.

I'm surprised that the mac575 can't run on 120, but based on the manual it looks like the magnetic ballast is the issue, just make sure you flip the wires around based on whether he gives you 208 or 240, whenever a solution is made.