A ground fault that hid in plain sight for three days

I was troubleshooting a random breaker trip in a 1970s office building last week. I checked all the outlets, tested the load, and even swapped the breaker, but it kept happening. The issue turned out to be a single, old-style fluorescent light fixture in a drop ceiling. Its ballast had a tiny, intermittent ground fault that only showed up after the fixture had been on for about an hour. I spent two full days on the wrong path before I found it. Anyone else have a story about a problem that was way simpler than it seemed?

3 comments

3 Comments

cameroncarr24d ago

Had a similar one in a 90s house with a fridge on a GFCI outlet. It would trip maybe once a week, always at night. I replaced the outlet, the cord, everything. The real problem was a tiny, slow drip from the ice maker line that would only hit the drain pan heater after the freezer had run a long cycle. Took forever to find that.

cameroncarr24d ago

Man, it's wild how often the real issue is some tiny, hidden thing that only happens under perfect conditions. Like a car that only rattles on Thursdays when it's over 70 degrees. You chase the obvious stuff first, but the fix is always some weird, specific chain of events. Makes you wonder how many other problems in life are like that, where the cause is totally separate from where you see the symptom.

umaanderson14d ago

Ugh, that is the WORST kind of hunt. It's always that ONE fixture or appliance you don't even think about. I had a mystery trip that was a cracked lamp holder in a closet light. The screw shell was just BARELY touching the fixture body when the bulb got hot and expanded. Took me a week to even look at it.