Can someone tell me if GFCI receptacles designed for permanent installation are required by NEMA, UL, or some other body to open both the line and the neutral conductors?
By design they would not work if they did not protect both lines. They have a current transformer in which all conductors of the circuit pass through. As long as all current that goes out to load(s) on any conductor returns on other conductors passing through the CT, the CT sees a net of zero and has no output voltage to run the trip circuitry.
I don't know what UL standards are, but all I have ever seen interrupts all protected lines, and I am guessing that is a standard also.Thank you, kwired, but the question is when the ground fault CT reaches its threshold and trips, will it open the line and the neutral pathways or just the line? And is this required by UL or NEMA?