Last year I installed an old GFCI outlet in a switch box. As verified with a multimeter, the white wire is neutral, and the black wire is hot. Note that this picture was taken after I took off the wire nut connecting the three white wires. At the time I installed it, everything worked fine.
Yesterday, I plugged an AC outlet tester, and it reported a swapped hot and ground. When I tested the outlet with a multimeter, I found that both prongs (as measured at the screw termminals) were were 120v to ground, and there was zero voltage between them. I replaced the outlet with a new one, and everything seems fine now.
- How could a GFCI fail this way?
- Is it likely that the GFCI should be thrown away?
- Why would this not trip the circuit breaker?