I need to add in a 220v circuit for a welder in my shop.
I have a seperate panel, and in that panel plenty of room for a 2-pole breaker.
There is already 3 x 220v 20 amp breakers in there, all on 12ga. wire.
The question is.. if I need to drop in a 30a or 40a breaker, what size wire do I need?