I have a single 15A 1P breaker that trips every time it rains. This is a relatively new problem since I upgraded the main panel in my house from a very old one (that never had any breakers trip). House was built in 1961.
I was uncertain that it was necessarily the rain, but the pattern is unmistakable at this point. The breaker will stay on and work fine, then about 12 hrs after it starts raining it will trip. If I try to flip it back on in that time, it will immediately trip again. Once the rain has stopped for a few days I can turn the breaker back on again and it will stay on.
The breaker only supplies power to a few lights and the igniter/lights/fan for a gas range. The roof of the house is in poor condition and will be replaced soon, but I'd like to fix this wiring issue regardless.
Any tips on how I can diagnose exactly where this wiring issue is? I unfortunately don't have attic access to this section of the house and I'd prefer not to cut into drywall unless I know where to cut.
Edit: I found it! Few photos below - at some point, it looks like somebody knocked an exterior receptacle off the wall and when they tightened it back down, they pinched the hot wire against the metal box. I suspect the rain gave it a better path to ground, which caused the breaker to trip.
This receptacle wasn't accessible until recently (we have been having a high deck replaced so there has been no way to get to it) but I will note that I had three electricians look at this and all three just installed a new breaker...