strange switch feed wire issue
A tenant reported that a light was out in their apartment. I removed the switch and used a home-made test light to check for power to the switch. There wasnÂt any. I then went to the basement to track down the feed wire that was leading up into the bedroom. I found it and followed it to the junction box. I tested the feed wire to the junction box to make sure it had power and then reconnected the line. I then went back up to the switch and found that my test light lit up twice, but not again. I also noticed little sparks as I used the test light and rubbed the wires along the exposed switch wires. The circuit breaker does not trip.
I used the test light in another location after I checked the switch (to make sure the test light still worked). I thought that the exposed portion of the switch feed wires were corroded? so I scraped them and I was still unable to get the test light to light up. I did see the tiny sparks occasionally again though.