GFCI not powering on

Question

I recently replaced a regular outlet with a GFCI. This is on a 15A circuit that powers this outlet as well as 2 outlets downstream.

The GFCI and the other 2 outlets worked fine for about 2 weeks. Had a family member plug in their hair iron in one of the downstream outlets and noticed there’s no power.

I’ve removed both of these downstream outlets and verified that there weren’t any burnt wires or other anomalies.

In addition, at the GFCI outlet, I have re-checked that I had the load and line wires are in the correct slots. The little LED light in the GFCI doesn’t come on and pressing the reset and test buttons doesn’t result in the typical “click”.

I tried plugging in a 0.5W LED night light in both of the downstream outlets and it results in the LED night light coming on dimly.

Tried swapping the GFCI to a different GFCI - same behavior. I took the GFCI that I had in place here and put it in a different spot and it works fine.

Next I disconnected the load wires and verified there’s no voltage at the downstream outlets. With just the load wires at the GFCI, I still can’t get the test and reset buttons to click. Similarly, no GFCI LED indicator.

Finally, I took the GFCI off completely, turned the breaker on/off 3 times to measure voltages, which are listed below:

1. Reading 1. Hot:neutral: 86-88v (readings kept fluctuating)
2. Reading 1. Hot:ground: 86-88v (readings kept fluctuating)
3. Reading 2. Hot:neutral: 81-83v (readings kept fluctuating)
4. Reading 2. Hot:ground: 81-83v (readings kept fluctuating)
5. Reading 3. Hot:neutral: 91-97v (readings kept fluctuating)
6. Reading 3. Hot:ground: 91-97v (readings kept fluctuating)

I’m lost at this point. The outlet box where the GFCI is has the hot wires and neutral wires wire nutted together in their respective wire nuts.

Is the changes in voltage readings an indication of the circuit breaker going bad?

Any advise would be greatly appreciated!

Answer 1

You have a partial-open hot indication where the GFCI receptacle is installed. If this happened in my home, I would go straight to the panelboard, wearing gloves and safety glasses, remove the cover and test the voltage at the circuit breaker.

Normal voltage at the circuit breaker means the problem is between the breaker and the receptacle. This includes any loose wire or splices at or near the breaker.

After eliminating any possible trouble in the panelboard, I would know the branch circuit is loose or damaged.

Turning off the circuit breaker will help you figure out if anything else is on that circuit.

Answer 2

I will provide answer after this statement you have provided: "Finally, I took the GFCI off completely, turned the breaker on/off 3 times to measure voltages".

I read that to mean that you decided to remove the outlet and check the voltage on the wires, between the hot and the neutral and you found out those low voltage readings as you have stated.

Voltage drop is caused by some form of resistance that is between the supply source and where the voltage reading is taken.

Resistance is caused by some form loads, bad wires, bad contacts, corroded wire etc.

If there are other outlets between where you are measuring and the breaker switch, check all them contacts, outlets etc.

If there is none and the outlet box is the first one being fed from the breaker switch, turn off the breaker switch and remove the wire. Trace the wire to its insulation and look at the neutral wire associated with it.

Remove the neutral wire as well.

Now you have the black and the white wire feeding that outlet. Connect the black and the white wire at either end, be it at the breaker side or the outlet side. Then at the other ends check for resistance. This is ruling out the breaker switch and the outlet as the culprit.

That is how you will test the so called circuit between the breaker and the outlet you have asked in your statement:
"Understood. Can someone please advise how do I diagnose the circuit between the breaker and the regular receptacle/previously installed GFCI?"

Now with respect to the actual breaker switch, you can also test that switch just the same. Turn off the breaker, remove the wire. Turn the breaker back on. Check the voltage between its contact and the netural bar.