Conduit Cutter

Issue with a GFCI breaker and in a metal building. ?

I've recently built a 30 x 40 metal building and to pass inspection I installed 2 lights and 3 plugs. Everything is has it's own breaker running though conduit from the breaker box to the plugs and light. My reason behind this was so that there would be less to inspect. After the inspector did is thing I was going to install more plugs. They require that I have the 120v plugs on a GFCI and my lights on an Arc Fault breaker. My plugs work fine when I replace the breakers with standard breakers. You can plug anything in and it will run fine. I can run my welder or plasma cutter off the 220v plug without a problem. When I install the GFCI breaker it doesn't matter what you plug in it trips the breaker. I can't figure out what it is, if it's a problem with the ground or what. Is it possible that I've gotten a faulty GFCI breaker? Three in a row seems unlikely. I'm just stumped on this problem.

GFCI outlets is a good solution, for the reasons mentioned and the fact that you can have inductance from circuits running parallel(especially with a metal building. Get the outlets and replace the breakers.

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