Bad Neutral Wire on GFCI Circuit?

[rgnkenpo]

It looks like I am in a jackpot. Before I go through this time consuming repair, I would like to please ask for opinions whether I am on the right track. GFCI has popped it's breaker and won't reset. Replaced GFCI outlet. Same issue. Have disconnected all outlets in circuit. At outlet #2 connect line voltage from GFCI works ok. As soon as I connect the wires to the disconnected outlet #3 the GFCI pops. For testing I replaced the GFCI with a standard outlet. 3 prong tester lights up as correct connections. Testing line voltage at outlet #3 location shows 124 VAC to Ground. Same test to Neutral shows 112 VAC. Is this 12 volt drop enough to trigger the GFCI, and does it show the neutral wire is bad? Thank you so much for your advice on here. If I am wrong where do I go next? You guys always save me on these little odd problems.

 

[ptonsparky]

I don't believe voltage drop has anything to do with a GFCI tripping. It is looking for an imbalance of current. Hot & Neutral current must be identical. Make sure your neutral is not being shared as in a MWBC.

Is this a new installation?

 

[rgnkenpo]

It is an existing 20 year old residence. I don't see any signs of it being a neutral share. I am now at a complete loss as to what might cause this issue. I really appreciate your insight. Thank you.

 

[ptonsparky]

It is an existing 20 year old residence. I don't see any signs of it being a neutral share. I am now at a complete loss as to what might cause this issue. I really appreciate your insight. Thank you.

Have you checked your circuit to see if it's faulted? Megg it.

 

[synchro]

As soon as I connect the wires to the disconnected outlet #3 the GFCI pops.

It sounds like there could be damaged conductors from #2 to #3. One possible scenario is that the neutral is open and you're seeing a "phantom" voltage of 112V from hot to neutral, but there's also leakage from hot to ground that is causing the GFCI to trip.
I assume there are no other receptacles or loads on the circuit beyond #3.
A suggestion is to disconnect only the neutral that feeds #3 from the #2 location and see if the GFCI still trips. If it still trips then the neutral is not the cause of the trips, but there might be a lack of continuity on the neutral between #2 and #3 that's causing a "phantom" 112V L-N voltage (which would be a separate problem that needs to be fixed).

 

[rgnkenpo]

Thank you for this information. More background. There are a total of 7 outlets on this circuit. Every outlet has been removed just leaving the wires exposed. To see if the neutral from Outlet #2 to #3 is bad I laid 12/2 Romex along the floor. I put a new Neutral wire into #2 on the load side. GFCI does not pop. Connected that new wire to #3 line side. GFCI does not pop. Connect remaining 4 ea. outlets one at a time. Circuit works fine. I guess at this point I have a bad Neutral from #2 to #3. Now how to replace that in the wall. I think I can get the #3 side replaced by taking out the medicine cabinet above it. The #2 side is trickier. There is a 6' permanently mounted mirror to the left and a stud to the right. And of course there is very little room in that area of the attic to work. Thanks for all your help guys. Please let me know if i am still off base here. Thank you.

 

[Fred B]

If it has worked for 20 yrs and suddenly stopped and with your trial/error testing method you seemed to confirm issue is between 2&3. Likely to find rodent had chewed into wire, I've seen that more than a few times where a squirrel or mouse chewed thru the wire, even found one that the mouse was never going to chew on another wire, mouse dead with jaw still clamped to wire.

 

[synchro]

I guess at this point I have a bad Neutral from #2 to #3. Now how to replace that in the wall. I think I can get the #3 side replaced by taking out the medicine cabinet above it. The #2 side is trickier. There is a 6' permanently mounted mirror to the left and a stud to the right. And of course there is very little room in that area of the attic to work.

Would it be any easier to feed #3 with a cable from the GFCI receptacle directly instead of daisy chaining from #2?

 

[retirede]

Has the homeowner mounted anything on the wall lately?

 

[LarryFine]

Sounds like a neutral-to-EGC fault. I wonder whether it will hold with the EGCs temporarily disconnected.

 

[Hv&Lv]

Sounds like a neutral-to-EGC fault. I wonder whether it will hold with the EGCs temporarily disconnected.

This is what I suspect also. The neutral is faulted or rubbed through and in direct contact with the bare ground wire.

 

[rgnkenpo]

Thanks guys. But Fred. Gross. There's no rodents in the attic. Ha ha. And to answer Retiurede's question, no nothing has been mounted to any walls and not in this pathway ever. My suspicion at this point is that when installed a staple was hit too hard and the wire just over time degraded. Not completely sure. I think at this point I will leave the master bathroom as it's own circuit and run a new circuit to other bathroom and for the other four outlets. Thanks for everything guys.

 

[ceb58]

If it has worked for 20 yrs and suddenly stopped and with your trial/error testing method you seemed to confirm issue is between 2&3. Likely to find rodent had chewed into wire, I've seen that more than a few times where a squirrel or mouse chewed thru the wire, even found one that the mouse was never going to chew on another wire, mouse dead with jaw still clamped to wire.

Found the same with a mouse still attached to a line for a dishwasher, what a mess

 

[ramsy]

can get the #3 side replaced by taking out the medicine cabinet above it.

If vanity light above medicine cabinet, check the light J-box for loose wires.

 

[Chamuit]

I was wondering if there is some device between #2 and #3 that you are not aware of?

 

[abrace]

GFCI has popped it's breaker and won't reset.

Did the breaker pop as well or just the GFCI? If just the GFCI then I agree it may just be a neutral to EGC fault.

If the breaker itself is also popping, then the problem lies elsewhere.

 

[Dennis Alwon]

Find the middle of the circuit and disconnect wires. Now see if the gfci trips. If it does then the issue is between the gfci and that receptacle. Now work back doing the same thing until you find the issue. If the gfci doesn't trip at halfway start disconnecting as before till the issue is figured out. It may just be an equipment grounding conductor touching a neutral in the outlet box.

 

[kwired]

This is what I suspect also. The neutral is faulted or rubbed through and in direct contact with the bare ground wire.

Or some other grounded object.

 

[kwired]

Find the middle of the circuit and disconnect wires. Now see if the gfci trips. If it does then the issue is between the gfci and that receptacle. Now work back doing the same thing until you find the issue. If the gfci doesn't trip at halfway start disconnecting as before till the issue is figured out. It may just be an equipment grounding conductor touching a neutral in the outlet box.

Think he has already narrowed it down to something is wrong between outlet #2 and #3.

 

[rgnkenpo]

Guys, thank you so much for your help with this. I appreciate this forum so much. Now, I have to say I owe everyone a huge apology. Chamuit, you nailed it. Between #2 and #3 there was another outdoor outlet that I wasn't aware of. That's why my test to replace the neutral between 2 and 3 worked. That outdoor outlet was bad. To make you feel better I paid huge dues on this. I was in the attic for over 4 hours trying to replace the cable before i found this outlet. Please accept my deepest apologies everyone. Live and learn, and hopefully my back will recover soon. Thank you again.