Hi Grant: The amps you're talking about, are welding amps at low voltage, around 40-60 volts. Your welder is a transformer/rectifier, it is just like a huge battery charger. High voltage in, low voltage out. Low current (amps) in, high current out. Look on the nameplate, it'll tell you what size 2-pole breaker to use; probably 40-50. When all else fails, read the instructions, eh? Good luck & Merry Christmas to you & yours.