Residential Circuit Debug

Press reset on the GFCI.

I wish it was that easy. The test button won't trip the reset button which is why i thought the GFCI was broken.

Guest,

Usually testing for voltage from hot to ground in a GFCI will cause it to trip, for the same reason the 'Test' button trips it. Another clue that you have lost one of your connections or miswired the GFCI.

Sir,

Check for voltage in any socket with a Tester. If you find voltage ( Tester glows in both socket points) then it indicates broken neutral. Then you will voltage betweem N & E. Also check up the incoming neutral to the main board for your flat.

There may be a break in the earth line connected to the main earth .

Manroop.Chennai.

Guest, First - welcome!

Second, From your terminology and descriptive details I must assume you are in the US.

Third, If you have not misstated your details, your biggest clue is being able to measure 115 volts from neutral to ground.

This should stand out to you as highly unusual since on your system they are supposed to be bonded together in a couple of specific places, keeping them quite close in potential. 115 volts is NOT quite close.

A tiny bit of deductive reasoning later and you have come to understand why I voted Manroop's answer a good one. Obviously your Neutral has lost its bond to your ground at some point between the GFCI and your breaker panel.

The next piece of your puzzle is what is the source of the 115 volts on the neutral?

In your system, you only have two possibilities; Line A or Line B, the 2 hot legs.

How does that potential get onto the neutral? Through a load or loads, to the point where all the neutrals are bundled together. Since the link from there back to the panel ground is loose, corroded, broken or otherwise compromised, you read the 115 volts to ground from there.

I usually look for a junction in a box where someone tried to put too many neutral wires in a wire-nut, or used a crimp style connector which has broken the wires up inside the crimp sleeve.

Think. Where have you recently made neutral connections? Check there first and save yourself a lot of time and frustration.

Regards, CJM

Is it possible you have a device on in the circuit and you read the voltage on the neutral through that device and lost the neutral as suggested earlier.