I recently installed a GFCI breaker due to a recessed floor outlet wiring burning out due flooding from storms.

When the electrician connected the GFCI's white pigtail wire to the neutral block the GFCI breaker would trip. He checked all the wiring and said something about the neutral used for another circuit, so he left the white pigtail unconnected and said the GFCI will still work properly, just the test button will not function. Is this correct? as I find it hard to believe the circuit is really protected without the white pigtail wire connected.

  • Does this so-called "electrician" have a license? Did he need a permit? Is an official inspector coming to check on it? That could be your answer, if the installer doesn't immediately agree to "make it right". – Upnorth Oct 6 '17 at 20:37

The GFCI absolutely needs its neutral wires

He can't make it work and he's trying to walk out the door. He needs your signature on a piece of paper, so he futzes with wires until it works, fumbles an excuse, gets you to sign, gone. What are you to say to his face?

In effect, he challenged you to either accept things as-is or be discourteous. You chose to be courteous. Standard contractor play.

If you read the instructions for the GFCI breaker, he certainly did not install it according to the instructions, which means the work is illegal under NEC 110.3b ( listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling ).

There's a real problem, likely a hard one

Most likely he found to his dismay that the circuit's neutral was being shared by another circuit... either a load grabbed this hot and another circuit's neutral, or vice versa. Or alternately, one of the loads on that circuit actually does have a ground fault -- people always forget about that possibility, but that is the entire point of a GFCI, after all! He didn't want to spend half a day doing a "bug hunt", so he dodged the issue and got paid.

Sometimes it is a systematic version of that thing, called a multi-wire branch circuit -- but those are easy for any competent person to spot. And very easily fixed: fit a 2-pole GFCI and done. So I doubt it's that.


GFCI's tend to have problems with multi wire branch circuits (2 hots 1 neutral 1 ground on 2 breakers) this used to be a very standard wiring practice but with AFCI & GFCI devices required just about everywhere they are becoming less common because depending on the model they tend to trip quite easily, this may be the problem but I would want to use a megger and ring the wiring out since you had a meltdown it may actually be tripping because of damaged insulation.

  • Isn't the purpose of a GFCI to compare the current in the hot to the current in the neutral and shut off the circuit if they differ by too much? With the neutral pigtail disconnected, how can the GFCI measure the current in the neutral? (Also, doesn't the test button perfectly simulate a ground fault? If it doesn't trip when the test button is pushed, why would it trip if there was a ground fault?) – David Schwartz Oct 5 '17 at 17:40
  • Most work exactly this way comparing the hot and neutral. – Ed Beal Oct 5 '17 at 17:57

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