Yesterday afternoon, I had a GFCI switch trip. It would not reset. I figured I had a ground fault.
I left the home for a few hours and after I returned I was able to successfully reset the GFCI.
The only other factors worth noting are that before I left the house: a) it was raining outside and b) there was a crew from the city doing some work nearby some electrical power grid infrastructure (transformers, power lines, etc.). I did not see them physically on the poles but they had earth moving equipment. I don't have any idea what kind of work they were doing or if it was related to the electrical system at all.
What could possibly explain this fact pattern? In particular, how could the GFCI not be resetting before I left, then suddenly able to reset after I return? Could the problem have been caused (and fixed) from outside the home? Is this something I should worry about repeating and start looking for ground faults or doing some troubleshooting now?
Best Answer
A GCFI (or RTD) works along these principles: -
It monitors hot (live) and neutral wires and if it sees a current flowing down one wire that isn't flowing in the other wire (called a differential current) then the current transformer produces a voltage that is used to activate a trip relay (sensor relay). Notice the test button is used to create such an effect by forcing a small current through only the neutral wire.
If water (for instance) is dripping onto an AC outlet (imagine that is the yellow hand in the picture) then current flows through live (hot) directly to ground and does not flow back through neutral hence the current transformer is imbalanced and produces a signal that trips the relay and power is disconnected.
If the fault occurs inside an appliance then try removing the appliances and restarting the GCFI but only remove the appliances with power off else you run the risk of electrocution.