Breaker size for Welder (2024 Update)

[rsscully]

I am considering a 230v mig welder and need to add a circuit. The input amperage for the welder is 20a. Should I install a 20 a breaker or use a slighly larger capcity like 25 or 30 amps?

[Chris Friesen]

The simplest solution is to use a 30A breaker with #10 wire.

Chris

[Colbyt]

When it pulls current it is all at once. I would do what Chris said above.

[gfretwell]

This may sound too easy but what does the manufacturer recomend?

[Don Young]

If the welder is designed for a 20A circuit, there is absolutely no advantage to increasing the breaker or receptacle size. If the run is long, it may be advisable to increase the wire size. An oversized breaker will only give you more opportunity to overload or damage the welder without the breaker tripping, although breakers are not really intended to protect connected equipment. Higher capacity than needed is not somehow magically "better".

That said, it costs little more to install a higher capacity circuit if you think you might need it in the future. I personally would probably install #10 wire with a 20A breaker and receptacle. This could be easily upgraded to a 30A circuit.

Don Young

[Steve Barker]

a typical welder plug for up to 250a would be a 30a. Welders are way over rated, in addition to the fact that you will rarely (if ever) run it wide open. I'd put in a 30a plug with 10ga wire.

steve

[Steve Barker]

a good argument for putting in the 30A receptical, and 10ga wire, is for when he upgrades the welder when he finds that little one won't do what he wants.

steve

[gfretwell]

630.12(B) For Conductors. Conductors that supply one or more welders shall be protected by an overcurrent device rated or set at not more than 200 percent of the conductor ampacity.

It gets more complicated than that when you read all of 630 but this is what he was talking about. The manufacturer usually does this code thrashing for you in the manual when they tell you what the recomended circuit should be..

[SteveB]

It goes like this: If you are going to weld for four hours straight with the biggest wire and the highest settings, you will approach the limits of your breaker. If you are going to weld for short intervals, with smaller wire, and at the lower settings, a smaller breaker will do.

I have a Lincoln 175SP+ wirefeed welder. At the lower settings, it draws nowhere near the amperage as it does at higher settings. But, when I had the electrician do the breaker, he looked at the chart and suggested a breaker that was 5 amps over that amperage. You don't want it so oversized that it REALLY has to get hot to pop. But you don't want it kicking off when you're in the middle of a long run. I'd do a 25.

I'd also check with the manufacturer and see what they recommend. They want the machine to run right, and for you not to install it incorrectly and have a problem.

BTW, there are only two choices for mig welders. Lincoln and Miller. The rest are crap that are hard to get serviced or to find replacement parts for.

Steve, who learned to weld in 1974

[Steve Barker]

Oh, i guess the people who invented the wire welder don't know anything about them and don't have the highest duty cycle machines in the industry.

steve (who's been welding since 1969)

[Meat Plow]

Depends on the gauge of the wire feeding the outlet of your welder. Use 10 gauge and a 30 amp breaker, that's what I have here for my Miller 180 and it's input amps are 20.

[Mr jojo]

Yes I will be polite to all other welders