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Wiring for 30/50 Amp

Posted by garlicjim (My Page) on
Mon, Jun 6, 11 at 13:25

My shop is wired for 220 off a 30Amp breaker from the main box to a breaker box in my shop. The reason we didn't wire for 50Amp is because I hadn't used a heavy enough wire and didn't want to dig it up and start over. At the time I only needed 220 for my large compressor. It's about 30 feet away from the house.

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.

What I want to know is what can I do to use the welder at the shop. I have a 50Amp outlet below the main box at the house, but don't want to weld everything over there or drag out my SUPER HD 50A extension cord.

Can I not wire a 50Amp receptacle from a 30Amp breaker? Or can I not use a 50Amp breaker on the 30Amp bars? (At the shop).

I'm probably not wording this correctly, but I hope you can understand what I'm trying to do

Any advice greatly appreciated.


Jim in the Desert of NM

Follow-Up Postings:

RE: Wiring for 30/50 Amp

"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.

RE: Wiring for 30/50 Amp

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.



RE: Wiring for 30/50 Amp

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

The manual should have the installation instructions.

RE: Wiring for 30/50 Amp

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 ( 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.



RE: Wiring for 30/50 Amp

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).

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