MetalworkingFun Forum

As in when you are attempting to weld 1/4" plate full out at 90 amps and the breaker keeps tripping, the time spent walking back and forth to the breaker panel to reset it could have been used to lay beads instead - dropping your duty cycle...  

Seriously though, my little Millermatic 140 is rated the same way. The 20% duty cycle is based on 90 amps output with a 20 amp input. If you drop to a 15 amp input, to maintain that 20% duty cycle you have to drop the output amperage to 63 amps.

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Willie,
Is your wiring from the 15 amp. breaker too small to allow you to change to a 20 amp. breaker?

No, I'm good at home Steve. I put in plenty of 20 amp outlets along my workbench when I built it. If I need to throw the welder in the car to do a little welding somewhere else though, (relatives house for example) they don't have any 20 amp outlets.