GFCE and low voltage

[topaz54]

Hi folks,
New here so really don't know if this has been covered recently.
My wife informed me that an outlet with GFCI had stopped working today. No changes or repairs have been made in the house. When I checked the voltage at the GFCI it was only 20 volts.
Can a defective GFCI cause low voltage? Again, this just happened all of a sudden. No changes have been made to the system.

[topaz54]

I must add that the GFCI itself has not tripped. Just shows 20v when tested with meter.

[HayZee518]

be very careful and remove the faceplate. remove the two screws holding the gfci in the box and pull out the receptacle until you can see the upper two screws. now measure the voltage at these two screws with your meter. tell us what you got.

[topaz54]

Thanx,

I found a cluster of neutrals in the main service box that were slightly loose after noticing that I had 120v when connecting to the ground in the outlet box. Problem solved.
Perhaps I should have mentioned that I am not completely ignorant about home wiring. I just wanted to know if a GFCI outlet could cause low voltage before I tore everything apart or went out and bought a new one.

[HayZee518]

I suppose anything is possible. The gfci is an electronic circuit within the yoke of the device. there is a set of contacts that open and close. being that you are familiar with house circuits, did you ever hear of a current transformer? it is basically a wound coil with an epoxied jacket. there are two of them one for the neutral one for the hot. conductors from each leg go through each donut. the donut's output has two wires connected to the electronics. it measures the amps that goes through the donut and compares them. if there is an imbalance between the two it trips the circuit.
in electronics there's a passive integrated circuit called a comparitor. it receives two inputs and compares them and results in an output gate to a solid state relay, perhaps a triac which is connected to the output terminals of the gfci.

[topaz54]

Now you're just showin' off.

[HayZee518]

nope I been a license holding master and journeyman electrician for 42 yrs.

[topaz54]

Good to know there is a qualified expert here to consult.

[zaku]

i have the a similar problem but instead, my outlet stopped working just suddenly when i was using my toaster and hot water boil at the same time.

I pressed the "reset" but seems that the "test" button won't pop back up.
i then took out the outlet and measured the voltage across red/white wire, and bare copper wire, any combination gives me 3V on my meter.


by the way when i took the outlet out, i see an unwired black wire, the outlet is wired with white, red and the bare copper wire.

I don't know if i change a new outlet will work? how come i get 3V readings?

please help

[HayZee518]

looks like the circuit breaker tripped. the 3 volts is leakage current from either an induced voltage in your wiring or actual leakage across the breaker's terminals to ground.

[zaku]

thanks for the prompt reply.

I forgot to mention that I checked my main electric panel breaker and all of them are at the ON position, none tripped...

[HayZee518]

it may be just redundancy but physically throw the breaker to off then back on. sometimes they trip but the handle doesn't move to off or a trip position. square D pushmatic breakers show red or pink when they've tripped. once you have placed them all in the on position take a meter and read the voltage to the neutral bar for each breaker. once you have confirmed you have voltage here, go to the gfci and carefully remove it from the box. with the meter check for 120 volts at the top two screws. if no voltage or a low voltage check back along the circuit for an open neutral or open hot wire.

[zaku]

problem solved! it was as you said, the handle didn't move to the off or trip position that's why i thought it was not the breaker! I tried moving all handles to off and back to on and the electric outlet came back to life.
thanks a lot for the help