Got stuck for a full day on a weird voltage drop in a 100-year-old house

Had a job last week in an old brick house downtown, putting in a new panel and some door contacts. Everything was fine until I powered up the main board and got a weird low voltage reading on one of the zone loops. Figured it was a bad connection, so I started checking all my terminations. Two hours later, still nothing. Ended up tracing every inch of that 22/4 run, which was buried in plaster and lathe walls. Turns out, about six feet back from the contact, the previous installer from like the 90s had done a spice and just wrapped it with electrical tape that had completely degraded. The copper was green and crusty, causing a massive resistance spike. What should have been a 30-minute fix turned into an 8-hour hunt. Anyone else run into these ghost voltage issues in old renovations where you just have to find the one bad spot?

4 comments

4 Comments

the_claire1mo ago

Ever have a buddy chase a flickering light for days? My friend did that in a 1920s bungalow, only to find a rat had chewed the insulation off a wire inside a wall. It's crazy how one tiny hidden flaw can eat up your whole day.

paige3311mo ago

Ugh, that's the worst. Those hidden splices in old walls are absolute time vampires. You can check everything you just did ten times and it still points to a ghost in the system. It's never the obvious spot, it's always some janky fix from thirty years ago buried behind solid plaster. So much for a simple panel swap.

the_drew1mo ago

Last year I traced a dead outlet for three hours in my own house. Finally found a hidden junction box behind the kitchen backsplash, wrapped in ancient cloth tape. @the_claire, that rat story is too real, sometimes the fix is just as weird. I keep a cheap borescope in my tool bag now for exactly that kind of wall ghost.

jason_lewis31mo ago

Remember that flickering porch light my neighbor couldn't fix? Turned out a squirrel had stashed nuts in the outdoor fixture box and the shells were shorting the terminals. Just a pile of acorns causing all that trouble.