I was told you could use one of the hot wires and it would be cut down to 220. Also the power is three phase but the welder is single phase. Just trying to use the power we have to run the welder.

You were told wrong.

If you had 120/208 Y service you could get 208, but not 240.

There's no way to get anything close to 240 from 480 service.

Screwing around with power in a commercial building if you aren't an electrician is illegal in most places and INADVISABLE if you haven't a clue.

I'll bet someone is thinking they can run the 240V welder off 277V (480Y = 277 phase-neutral)

It MAY work, but it's nowhere near legal, safe, or recommended.

"Yes. The correct way is to hire en electrician who will know what to do.
I know I'll get flamed for this but from the sound of it someone is going to get hurt or killed at worst, or at least the magic smoke will be let out of your welder if you hook it up to this panel."

Not sure why anyone would flame for this answer - to me it is really the ONLY correct answer to give under the circumstances.

I was actually able to do some welding of the fitting on the end of conduit that inadvertantly touched a 480V leg. I also managed to trip the breaker on the 13KV->480 stepdown in the basement.

A qualified electrician could install a buck boost transformer from 480 down to 240 to meet your needs. You must have some sort of transformer and panel in order to get 120v. for receptacles, so it may be easier to install a 208 to 240 transformer. However, if you have a delta/telta 480 to 240 (that would be a 120/240v panel with a hi-leg) transformer youre in luck. A Qualified electrician can have you up and going with minimal fuss.

If there is a small office in this warehouse with a receptacle, there HAS to be a 120V panel somewhere. Depending on the actual electrical specifications of the welder, it MAY be able to be connected to said panel, or as others have stated, a buck/boost transformer will need to be installed.

The other option is to by a 3-phase welder. Miller makes them and I presume others do as well.

To me it doesn't matter if there is a 120 volt panel somewhere in the building or not. This is all pure speculation on the part of people on this internet forum. The fact remains that if someone posts a question on how to hook up a welder to a three phase 480V service they are not capable of doing the work themselves.

There is nothing wrong with the OP asking the question, there is however in my opinion only one correct answer to it and that was already given in the first response.

I have no problem giving advice for residential work but three phase wiring is absolutley no place for a novice or DIY. Anyone who needs to ask how to connect something to a three phase service is not qualified to do it. There are way too many varibles in the situation - just look at what people are throwing around on this board right now - Delta's, Y's, high legs, buck transformers, step downs, step ups - heck why dont we just recommend that they install a phase converter while were at it...

I recommend anyone who wants to jump into any electrical DIY project to first spend some time in YouTube searching for 120v arcs and fires and then 220 and then jump to 480V. Spend some time looking up electrical burn photos and then really think about 'just winging it'. This stuff will separate your mind from your spirit almost instantaneously.

Here is a link that might be useful: 480v Arc Flash Demonstration

Yep, and as I pointed out, even if you have 120 power in the building, if it's three phase it's likely to only be 208volts between phases.

Of course it's possible (but unlikely) to have a stepdown transformer to provide 240.

JMVD is right. The poster has no business doing this unless he is an electrician. The very nature of his question indicates he is not one (or incompetent).

It can be done is legal all depends on. Your welding machine.a miller xmt 350 vs can be run on 440 ot 220. You have to change the plug.

Take the cover off of the machine and see which color wire is positive, negative, and ground. The machine was running 3 phase power before, so one of the wires won't be used, just take that one put a cap on it and tape it up

Timothy, I'm not sure why you came here spouting drivel on a thread that is 8 years old. He doesn't have a Miller XMT 350 (which indeed has a larger range of input power configurations it will accept). He has a Lincoln. It wants 230V. It can not be changed "by plug" or any other means to run on 440. There's no "positive" or "negative" on the input side. The only thing you've got right is that it is a single phase input.

Wow, guys! Thank you very much for your advice. A few years later, I came across the same problem as the author of the topic. It's good that the Internet remembers everything. At first, I thought it would be better to call a professional electrician to minimize the risk of electrocuting or accidentally burning all the electronics in the house. Still, I looked at how much they earned here https://weldingnearyou.com/careers/welding-supervisor/ and decided that it was better to be a little careful and try to solve the problem myself. I watched a few hours of videos on YouTube and read this topic, and in the end, I solved this problem myself. Thanks again, guys!