I am installing an outlet in my garage for a 220v mig welder. The welder specs call for 30A breaker.
The outlet for the welder is only 2 feet from the garage sub panel. The wiring refernece charts I've seen say I can use 12 gauge copper wire for this short of a distance. Does this make sense? I would have expected it to say that 10 gauge copper wire was the smallest acceptable wire to use.
The reason I'm even asking is that I am also wiring the garage for an air compressor and an air conditioner. Both will be on their own 220V 20A breakers. They will be located about 30 wire feet (one way) from the sub panel. This will require enough wire that it makes financial sense to buy the smallest gauge that will work safely and meet code.
Accourding to this link http://www.elec-toolbox.com/calculators/voltdrop.htm I could even use 14 gauge copper wire.
Realistically, what wire gauge copper wire should I install in my garage for these tools?
Best Answer
The calculator you referenced is only appropriate for voltage drop and makes the disclaimer that the results of the calculation do not account for current specs or NEC. Any circuit fused for 30 amps must use a minimum of 10 ga copper or 8 ga alu. Longer runs may require an upgrade of wire size. In your case, use at least 10 copper for your welder regardless how far it is from the breaker panel. I'm sure one of my buddies here will have a NEC ref for ya.