Question about a weird voltage drop in a 1970s house

I was rewiring a kitchen in an old house in Boise last month and hit a wall. The lights on a new circuit kept dimming when the fridge kicked on, but only in the afternoon. Spent a whole day checking connections, the breaker, even the new wire. Finally, after about 7 hours, I found the issue. The original feeder cable from the meter to the main panel ran right through an uninsulated attic space. The afternoon sun was heating the cable up so much it was causing resistance and a voltage drop under load. Had to reroute about 20 feet of conduit to get it out of the heat. Has anyone else run into something like that where the problem wasn't the work you did, but something hidden from decades ago?

3 comments

3 Comments

the_elliot2mo ago

Classic Boise... the sun out there is basically a second electrical inspector with a grudge.

cole9942mo ago

Wait, the sun was the problem?

john6502mo ago

Yeah, the sun can really mess with things. The_elliot isn't wrong about that. Reminds me of a job where the glare off a west-facing window kept tripping a sensor every afternoon like clockwork. Took us a week to figure out why the system kept failing at 4 PM.