Just a thought weldequip (theres me hijacking someone elses thread) my portamig would be capable of running gasless wire? The wire feed unit has has a dinse plug on the back for + supply, supplied by a dinse plug with connecting cable from the back of the machine, the machine has the earth on the front. If i was to connect the front earth to the wire feed and the dinse connector at the back of the machine as an earth i have safely reversed polarity? and hence can run gasless? or am i not making sense?