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Our house is wired with a GFI outlet on the outside wall with the deck outlets and the crawl space lights wired thru it. It is on a 15a breaker that controls a few other outlets, which still work when the GFI is tripped. When it rains, the GFI outlet trips and won't reset until it's been dry for a few days. I've replaced all the outlets and weather covers and replaced the GFI outlet, but it continues to trip. Yesterday, a friend came over with a tester and it was dry enough that the GFI would reset. All the outlets checked OK and all the lights under the house came on. Last night it rained and this morning the GFI was tripped again and won't reset. Can you come up with any possibilities for fixing this problem?
 

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If you examined all the outlets, then the only thing to do is map out the circuit and start disconnecting to isolate the problem.
 

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Remove the load connections and see if it resets. If it does then connect the load terminals and break the circuit at another point and try to reset. Continue this until you determine where the problem is. Water is getting in somewhere. You need to determine where and seal it up.
 

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Bypass your GFCI with jumper wires and put a 7-1/2w incand. lamp in series with the ground wire that serves the cable downstream of your GFCI.

When it rains or you soak the area with a hose, if the voltage across the bulb reads from 0.6 to 1.0 vac to up to 120vac you've found your leakage path to ground. A normal reading would be less than 15 mVac.

Disconnect chunks of the cable until the leakage current goes away.
 

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Sounds like a loose underground wire somewhere. Is there a shed connected to this, or an abandoned outside receptacle in the garden or yard?
 

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Discussion Starter #7
GFI trips when it rains & won't reset

The GFI outlet is on the outside of the house wall. Nothing is plugged into the GFI outlet. All outlets and lights that are on this GFI outlet are hot wired through it. There are only one set of wires in and one set of wires out, so all the splitting is done under the house. Only those outlets that are on the deck would be considered a wet area. They all have new boxes and covers designed for wet areas. I don't know why the lights under the house were put on it, as it's an enclosed space under the house. All the wiring is run along the first floor joists and the only wires that are exposed to the elements are to three outlets, all of which have been replaced and all of which tested to work when the GFI had dried out enough that I could reset it. Can an outlet or a light actually work when the conditions are dry and then cause the GFI to trip when the conditions are wet? I guess the problem could be in one of the junction boxes where he made the splits to go to the outlets and the lights. I haven't found that yet, but it's not in a wet area.
 

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...... Nothing is plugged into the GFI outlet....
So far so good

Only those outlets that are on the deck would be considered a wet area. They all have new boxes and covers designed for wet areas......only wires that are exposed to the elements are to three outlets, ....

  1. A Wet Location cover has a specific definition. Are they Wet Location Covers?
  2. Is there anything plugged into any of the three outlets?
 

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In studying your illustration again. I would have to say they are weather resistant covers, although there are two doors, one to each receptacle. The covers aren't designed for permanent attachment of a cord as in your description of a wet location cover.
 

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Since there is nothing plugged into any of the outlets, the type of cover is not as significant as if one or more had a cord plugged in.

Water is getting in somewhere. You need to determine where and seal it up.
Joed is right on this, if you can't visually find where, then it is time to start with the garden hose spray test.

Start with the GFCI Location with a medium 5 minute spray. If no response, wait 10 minutes and go to the next outlet and repeat until the GFCI trips.

Remember the GFCI is looking for a leakage path that might be very close or at the end of the run. The leakage can be at any point downstream from the GFCI.

What would be your estimate that the total length of all the wiring downstream from the GFCI? Could it be up to 150' ?
 

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I have also seen receptacles that were full of insects, dead or alive. The rain would be absorbed in the bodies and trip the GFCI no matter how good the cover was. You need to troubleshoot while it is acting up and determine where the problem is.
 

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rain causes GFI to trip

The total physical distance (as the crow flies) from the GFI outlet to the furtherist outlet is probably no more than 60 feet, but they go in all different directions. . . some to the back of the house, some to the front. . . so the total wiring from it must be at least 150 feet.
I don't think it could be a problem with bugs or anything in the outlets or the outlet boxes as I've changed all the outlets, cleaned out all the boxes, installed new weather boxes for those that were exposed and installed new weather covers for all the boxes.
The puzzling thing to me is that any little bit of rain will cause it to trip. I've looked at all the wiring that's exposed to the elements . . . no more than 20 feet. . . and find nothing suspicious, looking for staples cutting into the side of the wire, etc. All the other boxes are mounted on the side of the house and their boxes are within the walls of the house.
Looks like I need to hire someone with a meter that can track down the problem. I'm at a loss at this point, but appreciate all your help. Thanks.
 

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150' of Romex will give about 1 mA of reactive leakage current. GFCIs are supposed to trip at 4 to 6 mA.
Must be something else or a very sensitive GFCI.
 

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I will repeat.

Remove the load connections and see if it resets. If it does then connect the load terminals and break the circuit at another point and try to reset. Continue this until you determine where the problem is. Water is getting in somewhere. You need to determine where and seal it up.
 

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puzzled for reason of trip, GFCI [line] after rain

I'm gonna go out on a limb. This is a far out theory, but still possible. Maybe there is an open [mechanical] joint somewhere and moisture seeps in around one of the outlets downstream (of the GFI recept.) That could cause for leakage current to be present and trip the device!!!:furious: for not finding the problem!!!
 

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another possible source of (creeping) moisture

Since you mentioned in one of the "back-and-forths" that ALL the connections to the lights and outlets are underneath the house, there's one possibly strong source for the problem. Unless the wires are in moisture proof conduit and the joints are protected against wetness, there could be conductivity to GROUND. I can tell you from personal experience that there is significant moisture in that location even when it doesn't rain!!!:(now! :)later!!!
 

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After a rain you might be able to find the leakage to ground with an ordinary ohmmeter. Let's say a passing value is >1 megohm.
 
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