GFCI tripping

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solis

Member
Went on a service call, residential call, GFCI in the garage was tripped, unplugged all load on the circuit, it reset fine. Any load applied would trip unit. Any load from any of the 4 exterior and garage outlets on the circuit. Replaced the GFCI, same thing happened, it reset, any load would trip the GFCI. took a plug apart, when the unit was tripped, got 76 volts from neutral to ground. I will be going back to trace wires and troubleshoot. Am I missing something basic? Keep thinking I am. Will bring another GFCI to see if it is just 2 bad GFCI's doing the same thing. It didn't seem likely but maybe?
Input?
Thanks in advance
 

growler

Senior Member
Location
Atlanta,GA
Sounds like a bad neutral on the line side to me.

Turn of power to the cicuit and check continuity between hot and neutral on the line side of the receptacle. Should be open unless there is a light or something else in the circuit on the line side.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
It was not two bad GGCIs.
If it trips only when a load is turned on, that is telling you that not all of the load current (maybe none of the load current) is going back through the neutral.
If there is a feed through to other wiring, try disconnecting that. There may be a ground to neutral connection downstream.
The voltage to ground on the neutral when tripped is just phantom voltage since the GFCI receptacle opens both hot and neutral when it trips.
 

solis

Member
Appreciate the feed back. I will look at the neutral. Since it "just went bad" wasn't thinking that any wiring had changed, How could a neutral to ground connection happen all of a sudden. Everything was fine until Monday, according to the home owner.
 

growler

Senior Member
Location
Atlanta,GA
Went on a service call, residential call, GFCI in the garage was tripped, unplugged all load on the circuit, it reset fine. Any load applied would trip unit. Any load from any of the 4 exterior and garage outlets on the circuit. Replaced the GFCI, same thing happened, it reset, any load would trip the GFCI. took a plug apart, when the unit was tripped, got 76 volts from neutral to ground. I will be going back to trace wires and troubleshoot. Am I missing something basic? Keep thinking I am. Will bring another GFCI to see if it is just 2 bad GFCI's doing the same thing. It didn't seem likely but maybe?
Input?
Thanks in advance

Sounds like a bad neutral on the line side to me.

Turn of power to the cicuit and check continuity between hot and neutral on the line side of the receptacle. Should be open unless there is a light or something else in the circuit on the line side.


After reading your problem again I may have given you bad advice.

You need to remove the GFCI receptacle and undo ground wires. Then check to see where you have continuity that you shouldn't. H-N, H-G, N-G.


Did you double check to make sure you installed the receptacle correctly? It's possible for any of us to get the line and load neutrals crossed ( Yes, I have done it ).

Normally GFCI problems are easy to trouble-shoot.
 
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