"I have a Lincon Arc Welder that will pull variable voltage, I normally use only 75 or less. The welder has a 125V plug on it. "

You sound confused.

Is the 50 amps the OUTPUT rating of the welder?

The instructions should specify a supply current, and it is NOT the same as the output current.

Arc welders are mostly a very large transformer to decrease the voltage from the AC wall supply to a lower voltage while providing a higher current.

Confused? Moi? You bet your boots (smile)!

As I said, or tried to say, it's quite versatile. Here's what the description says:

"Broad output ranges: AC 40 - 225 amps".

Do dat hep? Hope so.

As you can tell, I don't know that much about Watts, Amps, Horsepower, nuclear reaction and splitting atoms.

Regards,

Jim

The output range has relatively little to do with the input required.

The manual should have the installation instructions.

Actually, my question was more of a general question. The welder is an older one and there is no manual. I may just run 50Amps to the shop (overhead...no more digging).

I just thought there might be a way to use it on a lower amp
breaker which carries 220. Like you said......I'm confused.

Regards,

Jim

It is very unlikely you need 50 amps on the 125 V input side.

Look for the nameplate on the unit and post the information there (even duty cycle matters, so post everything).