GFCI breaker tripping during heavy rain

[Jonathan Joseph]

Our GFCI breaker will trip during heavy rain. It really needs to be a VERY heavy rain of decent duration - just like the thunderstorms we have been getting recently. I need to find the location of the fault so that I can resolve this problem.

The breaker cannot be reset until everything has dried up well enough (several hours to several days if more thunder storms come through).

We have both bathrooms, two outdoor outlets and garage outlets and door opener on the circuit. It gets annoying to have no bathroom lights for several days.

Unfortunately, on visual inspection, the obvious culprits, the external outlets (both located under eaves, with nothing plugged into them, and with protective metal covers) seem dry as dry. Everything else seems fine as well. So either the problem is very subtle (which seems odd since the it is only caused by ver unsubtle conditions), or maybe there is some other outlet on the circuit that I am not aware of the existence of.

Is there any way to track down the source of the fault or at least rule out particular locations without a lot of hassle? If there's no easy way, what is the best way to go about finding the source of the problem?

Thanks very much.

-Jonathan

[Bill]

Try unplugging everything including the door opener, then see if you can reset the circuit....

[w_tom]

Locate an AC current leakage either to safety ground wire or via some wire (inside wall or in appliance) to earth. The current leakage is something greater than 150 microamps. That's right - micro. All appliances have some leakage. So when the GFCI trips, the leakage in microamp range increases to the milliamp range. Find the microamp leakage and you may find the milliamp leakage. Should current leakage be in upper microamp range when GFCI does not trip, then suspect a 'usual' suspect.

Obvious and not waste time: you require both good eyes (the visual inspection) and something that provides numbers (ubiquitous 3.5 digit multimeter that can measure low, AC current). A neutral wire (after GFCI) too close to a safety ground wire can leak current in damp weather.

Generally someth> Our GFCI breaker will trip during heavy rain. It really needs

[Toller]

I had this same problem for years; two electricians said there was absolutely nothing wrong.

Then I took an electrical course and found one of my outdoor outlets was bad. I replaced it and have been fine since.

Do you know how the circuit runs? I found the problem by opening the circuit in various places to isolate the problem.

[Charlie Bress]

I would certainly suspect that one of the external outlets is the culprit. The next time it happens, remove the cover and use a hair dryer on an extension to blow hot air into and around the outlet. Do one for about ten minutes and then try to reset the GFCI. If this doesn't help, then try the other one. This might let you isolate the problem. You just might find that the seals on the covers are not fitting tightly.

Charlie

[Joseph Meehan]

A couple of replacement outlets and seals for the outside outlets will likely fix the problem and cost very little.

I would just replace them, but if you like you can try the drying them out with a hair dryer next them.

[Jonathan Joseph]

I am comfortable enough with my knowledge of electricity and wiring to do things like replace swithces, replace wiring that had been chewed through by mice, and add an outlet in the middle or end of a run. I am also comfortable using a multi-meter.

Unfortunately, I am not knowledgeable enough to follow your instructions for finding a current leakage. Thank you for responding though. I hope some of the simpler suggestions prove fruitful for finding the source of the problem. If I can find it, I think I can probably fix it.

-J> Locate an AC current leakage either to safety ground wire or

[Jonathan Joseph]

Wow! What a rapid response. Thank you for the suggestions. I will start with the easy ones.

-Jonathan

[w_tom]

Instructions were never posted for finding current leakage. I don't know how anyone could have followed them. Summarized (without any necessary detail) was how we would have located the problem. Only enough was posted to discover if you have sufficient tools and attitude.

First step is the most obvious. Visual > I am comfortable enough with my knowledge of electricity and

[George E. Cawthon]

Bathroom lights? I thought just the outlets were on a GFCI circuit, the old code was. You have only one circuit breaker for all that?

Anyway, it almost sounds like something is soaking for a while before it trips like a line that gets wet and slightly shorts to ground. Be sure that you locate every outlet and then see if any outlet is supplied by wire that is buried. Rather tedious, but if you can figure out how the line runs start at the downstream end and disconnect the line at the next box upstream and try the circuit breaker and keep working further upstream (toward the circuit breaker). Or, work the opposite way, i.e., work downstream from the circuit breaker.

[Jonathan Joseph]

Problem resolved!

Well, I guess starting with the simple things first is a good idea. Despite the fact that the external outlets looked high and dry, I tried the hair dryer technique on them. After this, the circuit would still trip, but I thought I detected a slight pause before tripping. I tried again after an hour and the pause was now slightly longer (maybe 1/2 a second instead of instantaneous).

I looked at the outlets again, and while dry, I did now notice that one of the them now seemed slightly corroded. When I removed it and looked in the receptacle, sure enough, I found a little water in there. It seems the water made its way in during the heavy rain, but by the time I looked, there was no external indication that anything had ever got wet. I dried out the inside of the receptacle, put everything back together and the breaker did not trip!

For now, I have sealed up the outside with a little masking tape until I can pick up and install a new outlet.

As for the lights in the bathroom being on the GFCI, it's probably because the particular type of fixture had a plug outlet in it too.

Thanks all.

-Jonathan

[RB]

I'd buy a bucket of GFI outlets and place one at each location where needed and remove the GFCI breaker. Then when any GFI outlet trips you know which one it is and can better address the source of the problem.

RB

George E. Cawth>

[w_tom]

If properly installed, then rain should never cause a GFCI failure. IOW all exterior outlets are covered by a water protective cover. Wires inside the outlet should have enough spacing so that water (condensation) cannot create a conductive path.

A neat th> Problem resolved!

[Sinbad]

In my experience, and in other threads, I learned that you don't want to put more than one GFI breaker/outlet on a circuit. They interfere with each other.

That said, I am having a similar issue with a string of outdoor lights I installed up my driveway. I had a guy with a ditch witch come and bury segments of outdoor 12 ga wire (the gray stuff that is supposedly ok to bury without a conduit) from lamp post to lamp post. 7 posts in all. He actually put the wire into that 1" black plastic tubing for further protection.

I have them all connected to a GFI outlet on my front porch.

In dry weather it all works fine. But after a heavy rain, the GFI trips, sometimes immediately, sometimes after a delay of seconds or minutes.

So -- typical water problem somewhere. I finally isolated it to one segment of buried wire, between posts 3 and 4. Disconnect the wire completely at post 4 (hot, neutral, and ground), and it still trips the GFI. Disconnect the wire compoletely at post 3, and the GFI no longer trips.

So apparently there is a leak somewhere in the underground wire run between 3 and 4. I suppose it's possible that the ditch witch guy somehow skinned some insulation off the hot wire, and when it gets wet, it conducts enough to earth to trip the GFI.

This is a bummer, because I don't know if I can pull the bad wire out and pull a good one in behind it or not. Maybe I'll just run that segment through some trees and call it good. :-)

Sinbad

[EXT]

Could be some water getting into lamp #3. If it is the cable pull it out of the tube and replace it. Otherwise what was the point in putting it into the tube.

[Sinbad]

Yeah, no kidding -- the whole point of putting it into a tube is to protect it. But not necessarily from water. More from digging. All the tubes are buried under the ground, so water can easily get into them. The gray outdoor cable itself is meant to be buried or just be outside, with no further protection. So it must be a bare spot in the hot line.

If I can even get the wire out of the tube, I'll inspect it, but I doubt I can pull it out. It's 50 feet long with curves along the way, and it's 12 ga. If I can easily pull it then I will just to see what happened to it, but otherwise I'll just do another run, up in the trees or something.

It's not the lamp -- I disconnected that.

Always something, eh?

Thanks for the reply.

Cheers, Sinbad

[trader_4]

It doesn't have to be the hot. If the neutral is making contact with ground that will also trip it.

[John G]

*When you put the outdoor outlet back together make sure that the gasket is good. Also caulk around the cover. I use GE Silicone 2 Gutter (Clear) ca ulk for this. Home Depot sells it.

Several months ago I posted a photo on my Facebook page of an outdoor GFI r eceptacle that was subjected to water infiltration. It looked as though so meone put a torch to it. The DIY installer mounted an open face weatherpro of lamp socket in the upright vertical position on top of the weatherproof box. Water would land on the open bulb and trickle down the bulb socket in to the weatherproof electrical box. In addition to replacing the GFI, I re placed the socket with a sealed fixture and generously caulked.

John Grabowski

[Sinbad]

Good point! I did not think of that. Should have though, because the GFCI compares what goes out the hot line with what comes back in the neutral, and when they don't match, then it disconnects, right? So anywhere it leaks to ground will trip it.

[gfretwell]

Most of the time this ends up being water in a box somewhere. I start by splitting the circuit in half. Pick a box in the middle of the run, remove the device and terminate the wire there with wire nuts, being sure the conductors are not touching the box. Let it run that way for a while and see if you still trip. Then work in the direction you have identified as the problem.

When you are putting boxes back together, it helps to point all wire nuts up and keep them toward the top of the box.