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I live in a rural area that has frequent power outages (Several per month. Less than a minute in duration). When the power is restored, several GFI outlets always trip. I am trying to track down the cause of these trips, as one of the outlets powers a livestock water heater (Which needs to stay powered during freezing months) for the safety of the animals.

The GFI outlets that trip are connected to a sub panel that is fed from the main panel. Turning the breaker that feeds the sub panel off and on also reliably trips the GFI outlets in question. I have reproduced this with nothing plugged into the outlets (And load side of GFI disconnected).

This problem has occurred ever since the GFI outlets were installed (Several years ago).

I am looking for the next troubleshooting steps to solve this issue.

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    It is possible that the panel is improperly wired, without a separate ground, or with the neutral and hot switched. These could trigger sensitive GFCIs.
    – Hot Licks
    Sep 4, 2019 at 21:10
  • Wondering if the circuit is close to capacity, and everything powering on simultaneously when the power comes back is simply exceeding the rating. A variety of devices (e.g. motors) draw significantly more power on startup then during normal operation; normally everything would cycle intermittently, but a power outage would synchronize the maximum loads.
    – brichins
    Sep 4, 2019 at 21:12
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    @brichins they state they have reproduced the trip with nothing plugged into the outlets/load disconnected. so load doesn't seem to be the issue.
    – Mr.Mindor
    Sep 4, 2019 at 22:38
  • @HotLicks thanks to my dyslexia and the topic at hand, my brain somehow interpreted your name as a suggestion to lick the hot wire. Needless to say I was concerned and confused!
    – Doktor J
    Sep 6, 2019 at 14:04

4 Answers 4

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Some brands of GFCI’s trip on power loss. I first found this when putting them in on a bathroom sink outlet that was switched. Every time the light switch was turned off the GFCI tripped when the switch was turned back on. I switched brands and the problem went away. I think this was an early safety that today some new GFCI’s make you press test then reset to energize the GFCI for the first time so I would change brands with one and verify the tripping is no longer happening before replacing them all.

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    I got to upvote this because it's a great story.
    – JACK
    Sep 4, 2019 at 15:09
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    Ed nailed it. Replaced the GFCI with a different brand and the problem has gone away.
    – cyclops
    Sep 5, 2019 at 11:56
  • This is one of those answers I wish I could upvote twice...
    – dalearn
    Sep 5, 2019 at 22:25
  • Why is it tied to the brand and not a design specification? Is there a way to verify this "feature" before you buy?
    – Nelson
    Sep 6, 2019 at 9:34
  • Look at the technical specifications if it says anything like “low voltage trip”. The GFI outlet I got also has this feature, and it is documented. Though that doesn’t rule out some manufacturers including this feature without documenting it.
    – user149408
    Sep 6, 2019 at 11:05
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Ed's advice is correct. For a time, some builders of GFCI devices considered this behavior to be a "feature". Undocumented, of course.

This is largely gone from the market, so I would cautiously buy one of a particular make/model, and see if it works as you like. If it does, buy more.

Too bad, it would make a nice feature for some applications, like a table saw.

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    If a buyer isn't under time contraints, then sometimes manufacturers will respond to email or phone queries. This saves the trouble of returning / reusing components in other circumstances.
    – Christopher Hostage
    Sep 4, 2019 at 22:20
  • Any idea what the justification for this "feature" was? It seems awful.
    – R.. GitHub STOP HELPING ICE
    Sep 4, 2019 at 22:30
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    @ChristopherHostage If you're under a time crunch, I suspect this is one of the cases where you'd benefit from going to a dedicated electrical supply reseller instead of a blue or orange box and asking the sales staff.
    – Dan Is Fiddling By Firelight
    Sep 4, 2019 at 22:32
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    Over here in the UK we use the term "active RCD" for a RCD that also disconnects on power loss and "passive RCD" for a RCD that does not disconnect on power loss. Dunno if there is any similar terminology in the US.
    – Peter Green
    Sep 4, 2019 at 22:34
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    @R..I was imagining you're doing something dangerous, lets say running the mains powered lawn mower. The power trips, the lawnmower turns off, you go 'oh that's odd' and wonder off to find out why the powers tripped. You turn the power back on, the lawnmower busts into life and consumes the neighbours cat. Whoops, shame it didn't have that safety feature.
    – djsmiley2kStaysInside
    Sep 5, 2019 at 18:41
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You might want to think about installing a GFCI breaker in the sub panel that controls the existing GFCI outlets and then replacing the GFCI outlets with regular outlets. In my experience, the GFCI breakers perform better than the individual outlets and last longer.

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The above answers are correct, but there is more potentially to this problem.

GFCI breakers, or ground fault circuit interrupters, trip if the current on the load wire is more than marginally greater than the return wire. This is done with the understanding that the electricity has to go somewhere, so if it's not being returned, it is likely hurting something or someone.

During a power surge, it may be that your circuit is shorting out somewhere. These shorts might be caught by an AFCI circuit breaker, or arc fault circuit interrupters. Where I am, these AFCI breakers are becoming required for all livable rooms in the house. If the excess electricity is arcing, then it might be arcing to the return, which the GFCI will not catch, or it could be arcing to some other destination which the GFCI might catch.

In the latter case here, something may seriously be wrong with either your circuit, or the devices on your circuit. In this case I highly suggest you check the circuit and devices for damage that could lead to harm to you or your family.

In short, in an arc situation, GFCI will not generally detect arcs in the wiring if it comes back to the return. These arcs can happen before a power outage, and can also potentially heat a circuit up and start fires. The only arcs they will catch are ones that find a new ground.

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