Thanks everyone for your comments. Turns out I didn't have enough #4
wire to run 3 wires the distance I wanted the outlet at so I went next
door to help my neighbor who'd building a house now and we were
talking about it and I mentioned I needed to go and get some wire, he
handed me his leftover roll of #6-3 wire he used for his stove. I did
call Miller and confirmed that I should use a 20 amp breaker, they
also said a 30 would work too so that's what I used. I don't think in
my projects I'll ever need it all. Hooked it all up and welded up the
first thing ever last night, a small welding table. It was alot of
fun, doesn't look so pretty but that will take practice.

Thanks again,
Mark