Thanks for your replies. Yes, this is a single phase/three phase machine. Had it come with only black, white and green, it would have been obvious. Some days you're just born to be dumb. Thanks again.

Just received my welder from Everlast. As I'm about to attach the plug to it, I see this odd marking on two of the input wires. The White and the Black have an adhesive tag attached which reads "1 X 220VAC". That seems to indicate that the "hot" 240VAC leads from circuit breaker ...