Chicago Electric Welding Systems
Dual MIG Welder
Model 97503
Welding Current=30-120 amps
Input Power =230VAC, 21 amps (Peak) at 60 Hz
Open Circuit Voltage (Max) 36 VAC

What size is the wiring to the outlet this plugs into... thats what determins breaker size.

For 21 amps, you will need to go with a 30 amp breaker. Need a 10/2 or 10/3 dependincg on outlet configuration