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I have a GFCI in the garage. There are several outlets downstream of it, most of which are outside, with covers on. Despite the covers, sometimes the rain can get in and trip the GFCI. Strangely enough, this pattern only happens in the summer. It rains in the winter too, so why is my GFCI not tripping when it rains heavily in the winter?

The circuit normally has two fridges connected directly to the GFCI, and a computer downstream, and nothing else. In the summer, once it trips for whatever reason, even removing everything else from the circuit, it will still trip afterwards. This is how I found that moisture could get into the outlets outside. Yes, fridges work hard in the summer, but the GFCI still trips with nothing on the circuit.

Note: The coil on the fridge (hot part) is facing the GFCI about a foot away.

I get that fridge compressors can trip the GFCI. I get the moisture tripping the GFCI with nothing else on the circuit. But why is the summer season a factor?

Edit Aug16 2020: I found the source of the tripping. I found a mystery box on a wall with a blank plate and a vertical PVC pipe running into the ground. The pipe had broken, allowing rainwater to get in. Although the wiring is insulated, there might be a knick in the romex further down, or some underground junction. It is possible that the heat difference between outside/underground caused some condensation to form somewhere bad. I prevented large droplets from being able to get in the gap, and the tripping has largely stopped.

I was also confused by the color of the visible wiring, as the sun caused the yellow wiring jacket, used elsewhere on the garage circuit, had faded and appeared white, making me think it was an unrelated circuit.

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  • Refrigerator in a garage in the summer (or in colder areas, in the winter) is not a good idea. Tremendous waste of energy and may not maintain proper temperature. Today's refrigerators have relatively low-power compressors/etc. because they expect to work in a narrow ambient temperature range. Feb 16 '20 at 1:24
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No they are not temperature sensitive. What may explain this: Are the GFCI receptacles rated Weather Resistant? WR receptacles have the electronics potted so moisture is not a problem. In summer with higher humidity non WR GFCI receptacle’s May trip from moisture but not heat.

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    Down here in Florida they trip a lot due to the humidity.... nothing else.+
    – JACK
    Feb 15 '20 at 23:37
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Remove the fridges from the GFCI

This is actually a health & safety problem. If the trip were unnoticed for awhile, the fridge would warm up and bacteria would bloom. If it were then reset, the food would re-chill and not seem spoiled.

A fridge is not the use-case for GFCI anyway. It's well-grounded, the electrical parts are totally inaccessible, and you're not likely to drop it in a sink!

Humidity is doing it

Most likely, it's not rainwater. It's condensation, accompanited with big temperature swings in the condensing range. Humid air gets into the receps due to barometric pressure changes (or just wind). Then it cools off and the moisture condenses.

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  • Cannot remove fridges from the GFCI. It's in the garage. Code says that those circuits must be GFCI. There's the garage circuit opening circuit, but running a cord from the ceiling to the fridge is super jank.
    – Kevin
    Feb 16 '20 at 1:17
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    @Kevin This is one of the rare cases where I advise violating NEC, or at least getting a variance from the AHJ, which they quite commonly give, because NEC is not a suicide pact. At the very least, if they won't budge on GFCI, you should have 3 separate GFCI receps - one for each fridge independently and one for the downline. Putting fridges on GFCIs with something else is nuts. Fridges do leak ground fault current; but 1 fridge shouldn't trip a GFCI. 2 plus outdoor outlets, too much. Feb 16 '20 at 2:38
  • In the case it was the fridge causing the trouble my state allows a dedicated circuit to fridge/ freezer to be non GFCI, but the other loads being removed they still trip, going WR rated GFCI will probably fix the problem.
    – Ed Beal
    Feb 16 '20 at 3:08
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    Well, at the very least put the fridges on separate GFCIs from each other and from the rest of the circuit. So that's three GFCIs, but it's safe. It's funny how people consider electrical safety to be real safety, and food safety to be fake safety I guess. Next thing you know, we'll have low oil level trips on fire pumps. Feb 17 '20 at 18:54
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As a layperson, I am skeptical that GFIs work in heat.

It was 118° here 3 days ago and 114° most of this week. I just took and infrared temp reading of the OUTSIDE of our Electric Pedestals, and they read 148°. I can only imagine the temperature inside where the electronics of the GFI are. (Possibly close to 180°)

I have a small RV Park that caters to Senior Snowbirds.

I have 57 GFIs outdoors alone on the property, that as of today I am giving up on.

For years I have replaced them so many times it is unfathomable. The only one that uses them is us, to plug in things like hedge trimmers and yard equipment. It says in the Park Rules, that they are not to be used by our guests.

Today I went out to try to find one out of the 57 that worked and could not. Some should be brand new, not used. I use to replace them all the time on a one by one bases. But I am over it.

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    Hello, and welcome to Home Improvement. "Tripping" and "failing" are different things. Are your GFI's outdoor-rated? Why do you think the inside of the pedestals will be hotter; is there a heat source inside? And, you should probably take our tour so you'll know how best to contribute here. Aug 16 '20 at 20:24
  • I will just delete my account. There are a lot more welcoming forums out there.
    – user122231
    Aug 16 '20 at 22:19
  • I'm not sure how I could have been more welcoming, while still giving you the feedback you needed. But if that's how you feel, then such is life. Aug 17 '20 at 13:03

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