My welder has been tripping the GFI on the circuit in the garage after I have been using it a while. I finally took the cover off and discovered the electrician saved himself, what? $2 and used a 15amp GFI, even though the circuit breaker is 20A like I specified. (Why didn't the building inspector catch this? Is it to code?)
Anyway, that is not my question. I turned the circuit breaker off in prep to replace the GFI with a 20A one. Went back to the outlet, and pressed the test button, as a quick test to make sure I had disconnected the correct breaker. The GFI trips. I'm like, doggonit, I didn't flip the right breaker. I hit the reset button, and it will not reset. Weird, I did flip the right circuit breaker, the GFI receptacle is tripping even though the circuit is dead.
Well, thats crazy! If the GFI is not tripping because of an imbalance of current going through hot to neutral, but instead tripping because the button itself is mechanically tripping the reset, what is the point of having a test button? It is not really testing the GFI, it is only testing the mechanical tripping function of the test button!
Am I mis-understanding what a test button is supposed to indicate?