Multiple GFCI Outlets Tripping at the same time on different circuits

[maxrott]

Dealing with a noodle scratcher.

Trying to figure out what has caused multiple GFCI outlets on separate circuits to trip at the same time.

Over the last two Wednesdays in the morning something has happened which caused multiple GFCI outlets throughout the house to trip at the same time.

First Event - 6:45am (no one in house awake)
3 GFCI oulets trip. 1 Wired directly off panel running computer equipment, 1 on the furnace circuit running a dehumidifer and 1 in an upstairs office.

Second Event - 8:30am exactly 1 week later
Same three GFCI outlets tripped and another GFCI located in the basement on it's own circuit with minimal load and this time the master bedroom 15a breaker also tripped.

Weather was fine on both days, low winds. There was a nasty windstorm 2-3 days prior to the first event which did cause a proper power outage.

Any thoughts on this one are appreciated!

 

[Lucien Nunes]

If the GFCIs in question have open-neutral protection, then a bad connection on the neutral to the panel that causes the neutral busbar to deviate from near-ground voltage could trip them simultaneously. I am not familiar enough with US GFCI outlets to know whether they now often include this functionality (which has been required in portable GFCIs for a while but not installed ones.) Obviously an intermittent connection of the neutral could cause equipment damage, and might indicate faulty bonding, so would need attention.

Have you had any flickering or brownouts, or symptoms of abnormal voltages?

 

[maxrott]

If the GFCIs in question have open-neutral protection, then a bad connection on the neutral to the panel that causes the neutral busbar to deviate from near-ground voltage could trip them simultaneously. I am not familiar enough with US GFCI outlets to know whether they now often include this functionality (which has been required in portable GFCIs for a while but not installed ones.) Obviously an intermittent connection of the neutral could cause equipment damage, and might indicate faulty bonding, so would need attention.

Have you had any flickering or brownouts, or symptoms of abnormal voltages?

Hi Lucien - thanks of the reply. I haven't witnessed any other abnormal behavior other than a a power outage a few days prior due to a storm.

I'm not aware if the outlets provide open-neutral protection. They are all standard 20a GFCI outlets like this:

https://www.lowes.com/pd/Eaton-White-20-Amp-Decorator-with-Wall-Plate-Outlet-GFCI-Residential-Outlet/1002337410

My electrician looked over the panel and said everything appears in order, no loose connections etc. He beleives it may be due to an external event. I spoke with the power company and they are not aware of anything.

I also have a Sense energy monitor and whole home surge protector. The Sense monitor watches for and alerts on a floating neutral which it has not detected. I beleive your point about an intermittent open neutral would likely be caught by this (in theory), correct?

Sense Content

sense.com

I have also checked all oulets\circuits for an open neutral and not detected anywhere - though if the issue is somehow intermittent that finding may not be useful.

Thanks,

Eric

 

[maxrott]

An update for anyone reading.

Happened again this morning. Going through my energy monitor records I have found that the meter recorded voltage spikes of 131-134V on both legs of the panel at the time of the previous two events.

I have also checked with neighbors and at least one other home on the street experienced a GFCI outlet trip during the same time.

Appears that the transformer feeding our street may have been damaged in a recent storm as this did start happening immediately after a particualarly bad storm which caused widespread outage in the region.

 

[Lucien Nunes]

Interesting. Hopefully the PoCo will swap that out soon before anything more permanently damaging happens to anyone's electrical goods.

 

[maxrott]

Interesting. Hopefully the PoCo will swap that out soon before anything more permanently damaging happens to anyone's electrical goods.

That is the phone call I am making this morning! Thanks for your help

 

[maxrott]

Resolution:

Spoke with the power company. They had investigated and found that there is capacitor bank 3 miles away which was being used to balance load in the mornings. We were able to match to the minute all 3 occurances of the trips and voltage spikes I measured in my home and while bringing the bank on\off line.

They are going to take it offline until summer when grid demand is higher to normalize the spikes coming through.