What size conductors would I need for a 10 ft. extension cord for a plasma cutter?
When it comes to extensions used for welding and high current draw, I would not factor the cord size based on amp draw alone. Essentially the biggest problem you will face is heat generated within the cord. This is increased if you keep your cord rolled up whilst using it (the electromagnetic effect leading to an induction field). What I am saying is that when I use the welder for long periods of time, my cable gets hot, and as a result the rubber gets soft, any time I bump or kink the cord there is an increased chance of a breakage.