GFCI tripping on old house wiring with no third bond wire

[powerplay]

In Canada in an old house with new NMD90 14/2 garage wiring connecting to receptacles and bathroom lights without the third bare "bond/ground", I've intercepted the cable from the panel with an GFCI receptacle to protect the ceiling fan with no bare "bond" reference to ground through pipe. The gfci simply does not reset. If the old wiring without a ground reference (outside the white common) is shorting out it would really have no where to go to trip the gfci that I can see? I checked visible connections, and although some sloppy connection to devices where made, the taped soldered parallel connections appeared ok. I am considering a possibility that the conductors insulation from stiff cables shoved into existing gfci receptacles crammed into ungrounded metal boxes are damaged at the metal connector, but really have no where to go to be able to trip the gfci? The same in another location... The original Siemens circuit breaker that is drawing no power did not trip when the gfci was taken out of the circuit... Could the gfci be too sensitive to some odd load?

 

[Little Bill]

In Canada in an old house with new NMD90 14/2 garage wiring connecting to receptacles and bathroom lights without the third bare "bond/ground", I've intercepted the cable from the panel with an GFCI receptacle to protect the ceiling fan with no bare "bond" reference to ground through pipe. The gfci simply does not reset. If the old wiring without a ground reference (outside the white common) is shorting out it would really have no where to go to trip the gfci that I can see? I checked visible connections, and although some sloppy connection to devices where made, the taped soldered parallel connections appeared ok. I am considering a possibility that the conductors insulation from stiff cables shoved into existing gfci receptacles crammed into ungrounded metal boxes are damaged at the metal connector, but really have no where to go to be able to trip the gfci? The same in another location... The original Siemens circuit breaker that is drawing no power did not trip when the gfci was taken out of the circuit... Could the gfci be too sensitive to some odd load?

Sounds like you have either a neutral or hot touching the metal box somewhere. It's probably not a good enough fault to trip the breaker. But a GFCI is monitoring for an imbalance in the neutral (grounded) conductor and the hot (ungrounded) conductors.

It would only take more than 6-9 mA for it to trip or in your case, not reset.
The GFCI is not "too sensitive", its doing it's job.

Also, make sure you don't have line/load reversed on the GFCI.

 

[drktmplr12]

Also, make sure you don't have line/load reversed on the GFCI.

This is easier to mistake then one might think. I recently bought a GFCI to replace in my kitchen.. The line side comes from the top and I have a downstream receptacle near the sink that is fed from the bottom. Turns out when I orient the GFI receptacle right side up.. the line side termination is on the bottom and load on top! I found this out after I powered it up and it would not reset. Reversed the connections and it works.

 

[GoldDigger]

One reason that some new GFCI receptacles come with tape over the load terminals. It very effectively tells you which is which.

Tapatalk!

 

[kwired]

Make sure you don't have a tap off this circuit that does not return via the neutral of the same circuit, or a neutral from another circuit that is returning via the neutral of this circuit - that will definitely cause this kind of trouble.

Add - you could possibly have an otherwise legal (at the time of installation anyway) multiwire circuit and have shared current on the neutral causing the tripping as well.

 

[powerplay]

Make sure you don't have a tap off this circuit that does not return via the neutral of the same circuit, or a neutral from another circuit that is returning via the neutral of this circuit - that will definitely cause this kind of trouble.

Add - you could possibly have an otherwise legal (at the time of installation anyway) multiwire circuit and have shared current on the neutral causing the tripping as well.

It was a long hot day, and I didn't think of that because it was simply an new cable to intercept out of the panel, but I think that may be the case. I figured it would be a can of worms, and was considering putting up an porcelain bulb holder like the original style at the time, but they requested a ceiling fan with metal pull chains and housing near a properly "bonded" fridge. If the metal connector cracked the insulation, eventually the breaker would go when both lines were compromised, but I assume the Gfci would not respond unless the metsl ceiling pipes were grounded somewhere?

 

[powerplay]

This is easier to mistake then one might think. I recently bought a GFCI to replace in my kitchen.. The line side comes from the top and I have a downstream receptacle near the sink that is fed from the bottom. Turns out when I orient the GFI receptacle right side up.. the line side termination is on the bottom and load on top! I found this out after I powered it up and it would not reset. Reversed the connections and it works.

I came across the same thing myself, and at first glance thought someone wired it up incorrectly. The common one I have usually seen has "line" on the bottom near the "bare bond", but after seeing "line" on the top, thought the constant power to be away from the bare wire made sense. I was under the impression the incirrect wiring would power the receptacle but not work when tested to shut off?

 

[kwired]

I came across the same thing myself, and at first glance thought someone wired it up incorrectly. The common one I have usually seen has "line" on the bottom near the "bare bond", but after seeing "line" on the top, thought the constant power to be away from the bare wire made sense. I was under the impression the incirrect wiring would power the receptacle but not work when tested to shut off?

Newer generation GFCI receptacles will not let power thru to the receptacle if reverse wired and "tripped". They need power applied during reset to actually get them to reset. So if you have one that is already reset - you can reverse feed it and it will work - but will not reset after it has been tripped. Older generation did not care if you reverse fed them, the receptacle outlet and the feed thru terminals were the same bus and if you back feed it will never interrupt anything unless something is connected to the "Line" terminals.


Other thing would be to make sure you don't have a GFCI that for some reason is defective and simply will not reset, connecting it to the line and not using any load side terminals should be a simple enough way to test this.