As the others have said, or referenced, the welder will require 50A *at
its maximum output* (225A). I don't think in 20 years that I have ever
run mine at more than 125A. So if I were adding an outlet in the
garage, say, I would run a 30A circuit just because I could use 10 ga
wire iso 6(?) ga. Cheaper and much easier to handle.

YMMV,
Bob