Wire size for 40A welder

Be advised, the welder will NEVER pull what it says it will. They are highly overrated. Besides a #8 would be fine for 40A. 10ga on a 30a breaker will work fine.

Steve Barker

If the welder actually draws 40 amps, #6 copper would be fine

Consider what would happen if you put in too small wire. You get to do it again, and pay more.

Do it once. Do it right.

What if you decide to get a little bit bigger welder? Or if you like welding, and use it enough to really heat up the wiring?

Copper is expensive now, but nowhere near the cost of doing it twice.

Steve

Wow, I wonder where they came up with that. The National Electrical Code shows #6 copper at 55 amps.

Neither -- #8 copper is quite sufficient for 40 amps. If you're using aluminum, then you need #6. But in no case do you need #4 for a load of only

Here's the site: I thought it shoul be higher than that....

Thanks

I'm no electrician so I'm not sure what they're giving the specs for but just think of it this way. According to that table, 14 ga is only rated to

Below the table, it does say "The National Electrical Code [NEC] requires their own cable sizing for premises wiring. Refer to the NEC rules to determine building wiring, as this page relates to electronic equipment wiring."

This is then followed by a sample list of wire guages and supposedly NEC-permissible ampacities, which I will *not* reproduce here because it's wrong.

Sounds about right.

Good luck, and stay safe.

I looked at that chart again, and it really is screwy. I was too quick to find a chart and did not spend much time reading all of it. So much for that POS chart.....

Thanks