GFI outlets tripped after power outage

Question

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.

Answer 1

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.

Answer 2

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.

Answer 3

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.

Answer 4

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.