My journeyman told me to always check for backfeed on a 240v disconnect, and man was he right

I was swapping out an old AC unit disconnect in this 90s house over in Mesa last month. The homeowner swore he flipped the main, and I saw the indoor unit was dead so I figured it was safe. My old boss, Frank, drilled into my head for years to test both legs with a meter even if it looks dead. I almost skipped it to save a minute, but I did it anyway. Sure enough, one leg was still hot from some janky wiring the last guy did. I mean, it could have been real bad. Now I test every single time, no matter what anyone says. Anyone else have a close call like that where an old tip saved your skin?

2 comments

2 Comments

sam175d ago

Honestly though, that extra step feels like overkill sometimes when the main is clearly off.

gibson.elizabeth5d ago

Yeah but that's exactly when you need the extra step. If the main breaker is off, you still have to check for backfeed or a shared neutral. It feels like overkill until you get bit because you assumed something was dead. Seen it happen, not fun. That five second check is way cheaper than a hospital trip.