ground wire runs hot (residential)

Thanks in advance for your replies. This one is challenging. A few days ago, I was using a grounded electric staple gun plugged into a grounded extension cord in a bathroom receptacle. I worked for about an hour, then the power cut off to all receptacles on the circuit. Not sure where the fault might be, I checked all parts of the gun, all plug connections and the breaker…all were fine. I unplugged & replugged the gun into the same bathroom receptacle and it worked again for about 10 minutes… then once again all receptacles were off and have been since. Breaker is still not blown. Before this, all receptacles on the circuit worked. I had never tested the circuit to ensure it was wired correctly.

To investigate, I used an electrical tester on the bathroom receptacle. In hot & neutral…no light. In hot & ground…got a light. In ground & neutral… got a light. Based on this, I put an ETCON Model CT101 (to test for properly wired circuits) into the receptacle. I got a reading that said “Hot/Ground reversed”. I plugged it into all other receptacles on circuit…same reading. I then unplugged all elements from all receptacles on the circuit, with the exception of a bathroom wall light also on this circuit. Circuit still read, “Hot/Ground reversed”. The circuit went from working fine to “Hot/Ground reversed” without any apparent change in activity. I have no power current on the hot lead, but there is definitely current on the ground. If I turn off the breaker, power goes out on the ground. I checked other circuits in the house, everything else is fine.

Any recommendations of what to do next?

 

You don't mention a GFI on this circuit, but since it's a bathroom, I suspect it has one, or it has a GFI breaker.

I'm not familiar with the particular tester you used, but could it be giving you a false reading due to a GFI being in the circuit? Try the tester on another circuit. If you find a GFI in your problem circuit, take it out, and try the tester on the power wires (before the GFI).

Check in the breaker box for connections. Do things look OK for this circuit (black to breaker/white and bare to neutral/ground bus)?

If none of this produces any informative results, start at the first outlet, disconnect the feed to downstream outlets, and test. Check that black is on the brass screw and white on the silver. If it checks out OK, reattach the downstream feed and go to the next outlet. Do the same disconnect/test/checking at each one.

 

Did one of the staples go into the wiring?

 

Thanks for your replies. I also received the following responses from a posting elsewhere:

1) Sounds like you might have an open neutral. The dime store receptacle testers will usually show hot/neutral reversed when there is an open neutral. If there was no hot you would not get the tester to light at all. Check to see if any upstream neutral connections are bad especially if the receps are "daisy chained". Also check inside the panel to see if the neutral is discolored on the buss. If it is, cut a fresh end and put it under an unused screw. And shut off the power! A neutral can kill you just as dead as a hot can! Brian

2) These type receptacle testers are good for a rough initial testing and wholesale testing of a bunch of receptacles..but after that, we need to get serious with a good solenoid type tester that also has batteries in it for continuity testing ...or we may be left trying to outwit these neon testers. Neon testers are not fail-safe. NEON IS CONSIDERED A ZERO IMPEDANCE PATH ,ONCE IT FIRES.
denis

----Thanks to everyone for your help! The final outcome:

I finally was able to test again today using a good solenoid tester. It was an open neutral issue & by checking all receptacles, I also found two GFCI boxes had failed on other circuits in the flat.

When I first tested the GFCI receptacle, the tester read 80V for the hot/neutral and 120V for the hot/ground. I found the open neutral in the breaker panel... the neutral was not connected. Odd, because it looked like the neutral had never been connected and the circuit stopped working only recently. It turns out there is not a true ground in our flat which I did not know. The ground and neutral is connected in several places, so likely what we were getting on the second floor was the neutral coming in on a ground wire for that circuit. The GFCI on that circuit must have ultimately failed causing the switchover. Once I switched the GFCI and attached the neutral to that breaker, everything worked perfectly.

Once again... a HUGE thank you!! All the best!
Chris