Ernie— Kinda tough to give wire and breaker size with no known specs. I don't know what you are suggesting when you say jump from welder to welder. I would say that 630.11(B) is the article for calculating the supply conductors and the load for the Service. At least that's how I'd call it. Bearing in mind all conductors must be protected at their ampacity per 240.4 and then there is the provision in 240.4(G) for welders. I've never been real comfortable with the fusing on conductors for welders but that's what it says and I guess there is a good track record. I know, let's ask the Design Professionals that question. I don't know what they will say since their kinda quiet on this issue.
