strange electrical problem solved

[Tom M King]

The lighting circuit in the mechanic shop has had a strange switch eating problem. About a year ago, the lights wouldn't work. I took the cover plate off the switches, and first try was a jumper wire across the lugs on the light switch. Lights came on, so I changed the switch, and it lasted about another year. Same thing again, jumper made lights work, changed to switch to just one I had. That one lasted about a week.

This time, when I tried the jumper, there was nothing. Pulled the switches out of the box, tested with multimeter....nothing. Took wire nut off hot wire in the box, checked, still nothing. I was Really not wanting to have to pull another wire thinking one possibility was a staple into one of the old wires too tight.

I pulled the cover off the breaker panel. Lug on breaker to that circuit showed nothing. Switched the breaker handle back and forth several times, and it became hot again and the lights worked.

That bad breaker must have caused arcing somewhere that burned up those switches. I had replacement breakers, so put a new one in, and it turned out to be an easy fix.

Intermittent problems are often hard to find, especially when one causes another fault in the system. I got lucky this time. Anyway, there are now all new switches in that circuit too.

[Jimmy Harris]

Intermittent electrical problems are the worst! Hopefully this fixed it. But if it didn't, I'd look at the light sockets next. If something is drawing a lot of amps, but not quite enough to throw the breaker in the first place, it could overheat both the light switches AND breaker over time and cause them both to fail prematurely. Like it could be a small short in one of the light fixtures that's not enough to flip the breaker. I've seen this happen, especially in fluorescent lights. So this could possibly just be another symptom and not the actual cause. Or, it could have been the problem all along. Time will tell. Like I said, intermittent electrical problems are the worst!

[Tom M King]

Thanks. I probably should have said that I did check it with a clamp meter when it was workign, and the circuit was only drawing a few amps. That was actually my first guess. That building has exposed NM wire just stapled here and there. I'd like to redo it all, but there's too much stuff in there. I throw the main breaker when I leave. Nothing in there needs power if I'm not using it.