Originally Posted by KTM640Dakar
The extension cord is what is hurting you. Plug the unit directly into the wall. You probably have a capacitor bank that is trying to load up along with the cooling fan kicking in. You can't use an extention cord if you want to draw the minumum amount of amperage from the wall outlet.
It could also be the machine protecting itself from low input voltage. Another reason to not use an extension cord.
Um, I'm pretty sure that any extention cord will increase the resistance of the feed side of the circuit and therefor slow the inrush current not increase it. An extention cord helped the problem so a longer one could in theory help it more. A machine that blows the wall breaker to 'protect itself' needs to be redesigned so that likely isn't it either but good try. If it were me I would suspect that the guy's breaker might be worn out from all the breaking. The fault is intermitent so I'd look there first.