Got a weird reading on a 20 amp circuit in an old house

I was working on a house built in the 50s, replacing some outlets. On one 20 amp kitchen circuit, my meter showed 122 volts hot to neutral, but only about 2 volts hot to ground. I thought my meter was broken at first. After checking everything, I found the ground wire in the first outlet box was just wrapped around the metal box and not actually connected to the circuit ground. The whole run was using the conduit as a ground path, and a loose connection at the panel had basically killed it. I learned to always check hot to ground voltage first, not just hot to neutral, especially in these old places. It was a good reminder that the neutral isn't always a reliable reference. Has anyone else run into a 'phantom ground' like this on old pipe work?

2 comments

2 Comments

felix_williams713d ago

That's a solid find. I've seen similar things happen when someone used a three prong outlet adapter on an old two wire system, just screwing the ground tab to the cover plate. It'll read fine until you actually need a ground fault path, then you get that scary low voltage. Makes you double check every "upgraded" outlet.

stellachen2d ago

Oh man, the "upgraded" outlet thing hits home. I once spent an hour trying to figure out why my new lamp was buzzing, only to find the previous owner just shoved a ground wire behind the drywall and called it a day. My test light looked fine too, until I actually touched the metal base. That was a fun little zap. Now I just assume every old house is secretly booby trapped.