2

Our kitchen is supplied by a multi-wire branch circuit to provide 2x 20-amp circuits. One circuit has the fridge and a single GFCI receptacle on it (the fridge is not protected by the GFCI receptacle). The second circuit has a GFCI receptacle followed by 2 additional receptacles on other walls. The neutrals for the GFCIs are not protected by the other GFCIs (I think this is called pigtailed). This circuit was last modified about 2 years ago and has been stable that entire time. The second circuit has a microwave and toaster oven on it, sometimes running at the same time which is definitely overloading the circuit as both have an audible change in sound when this happens (we do try to avoid this situation...). The microwave was also on a surge protector (which was rated high enough, but I have since read that the rating may apply to the entire strip and not each outlet).

In the last two weeks, the circuit has gone "weird". It appears as though sometimes the GFCI receptacle is almost but not quite tripping when placed under a small load (even just ~200W). The indicator light on it flickers green, sometimes flickering between green and red, but not tripping. During this flickering, the devices on the circuit lose power for an instant. However, there have been times when we have been able to still have the circuit under load without any flickering (like running the toaster oven, although at this point the microwave has been completely removed from the circuit).

So my questions are:

  • Why isn't the GFCI actually tripping? Or why is it almost tripping without an apparent ground fault? (I have checked the wires in the receptacles and they all look)
  • What needs to be fixed? Does just the GFCI receptacle need to be replaced?
  • Did overloading the circuit cause the damage (to the GFCI receptacle or whatever else)? [we always planned to add an additional circuit, just haven't gotten to it yet]
  • Is it possible the other branch of the circuit with the fridge has any damage to it (currently no symptoms though)
2
  • 3
    What happens if you press the TEST button on the GFCI? Sep 4, 2023 at 4:13
  • @manassehkatz-Moving2Codidact I have used the TEST and RESET buttons many times (with varying amounts of time between them) and it displays the same erratic behavior.
    – thaimin
    Sep 5, 2023 at 2:41

2 Answers 2

6

That sounds like series arcing, probably caused by a bad connection. Take everything apart and look for signs of overheating/burning/melting. When reassembling, be sure to only use screw terminals on devices - never the push-in-only “backstab” connections as they are a notorious cause of this sort of failure.

The lights on your GFCI devices are going out just because they’re losing power. Regardless, GFCIs don’t detect series arcing because that’s not a fault to ground. There’s also a chance the fault is upstream of the GFCIs and they can’t detect upstream faults even if they are to ground.

This is a serious problem and could cause a house fire. This is why AFCI (arc fault) protection is required on most circuits in the 2020 NEC.

1
  • If the fault is downstream from the GFCI, would it flicker? And I know this is a serious problem, and we are only using that circuit now while testing and trying to figure it out. The GFCIs have 3 ways to connect wires: the push-in slots (I never use those), the regular screw terminal with the wire wrapped around the screw, and a metal plate under the screw that seems to allow a straight wire but still connected with the screw terminal. I am using the last one, maybe I should switch to wrapping around the screw instead.
    – thaimin
    Sep 5, 2023 at 2:53
-3

First the GFCI has more than just 1 function, as most breakers it will fail on current overload, it will also fail on a residual current path down to ground, (neutral crossed with ground), for these reasons there is more than one reason for a GFCI to create problems, I believe the GFCI is the problem here.

Bullet point 1: The GFCI will not trip without over current or sensing a neutral path to ground, if the GFCI is faulty, (not good), this may cause the device to fail.

Bullet point 2: The GFCI is showing problems, this needs to be replaced ASAP.

Bullet point 3: Overloading would cause the device to trip, but putting the device close to overloading over a period of time, in my experience can create problems, an electrician would determine if an additional circuit is required or if the present circuit cable if sufficient for a higher rated GFCI, but it will be one or the other.

Bullet point 4: If in relation to this circuit, absolutely not, there is no correlation between the two.

2
  • 1
    GFCI receptacles do not monitor for overcurrent, but only ground faults.
    – nobody
    Sep 4, 2023 at 16:10
  • @nobody, I am UK here is not a GFCI == RCD if so it would be given an amp rateing, I believe this one is 20, if correct the device is both current and to ground reactive. Sep 4, 2023 at 23:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.