Possible ground fault

[2Busy]

I have a breaker tripping fairly often and I’m getting above my pay grade and safety rating in dealing with this, was hoping to get advice from those who know more than me before calling in a pro to deal with it.

I have a 120v 15 amp circuit of 6 outlets in the upstairs of our house that runs under several window dormers where we’ve had roof leaks in the past. There’s no load on this circuit other than when I’m doing some remodeling upstairs with a miter saw and some other power tools. The breaker has never tripped when using any of those tools (and the start up of that miter saw draws a pretty good number of amps). However, after a rain (but not every time it rains) it trips—and always when there’s no load on the circuit. This would be about every 2-3 weeks. I’ve tested every outlet to be sure there are no faults to ground or faults to to neutral, etc. No issues there.

So what does that leave? I’m thinking either a bad breaker or I have a problem in the romex somewhere that’s being affected by a roof leak (thought we had those dealt with but maybe not!). Does that sound right? Is there anything I’m overlooking? Unless there’s something obvious I should be looking at I’m ready to call in the A team. Thanks in advance for your input!

 

[wyliesdiesels]

What type of breaker? GFCI or regular?

No way for an outlet to have a fault like you mentioned.

 

[Showkey]

GFCI ? Yes, One of the outlet boxes or junction boxes is getting wet. Any chance there’s an outside outlet on this circuit that your not aware of.

 

[2Busy]

There’s not a GFCI outlet on this circuit. Not sure if the breaker is GFCI or not—is there an easy way to tell? To the best of my knowledge there’s no outside outlet either.

 

[wyliesdiesels]

There would be a test button on the breaker if it was GFCI.

 

[ddawg16]

If it's not a GFCI breaker (or AFCI), I'd start thinking a nail is sticking into one of the wires....and when things get wet, creates a problem.

But the bigger issue is the water problem.

"However, after a rain (but not every time it rains) it trips—"

That needs to be addressed.....it could be a much bigger issue down the road

 

[2Busy]

There’s no test button on the breaker, so not a GFCI. I’ve heard that breakers can go bad. Is that the next thing to check, before I go looking for water coming in? There are no obvious signs of water penetration but that doesn’t rule out the possibility.

 

[wyliesdiesels]

What brand and model breakers?

Whats the brand and model of the panel?

 

[njride]

I would find the home run and isolate from the rest of the downstream circuit, meaning leave that first receptacle attached see if it still acts up. Break the circuit in half and troubleshoot accordingly.

 

[Showkey]

The rain caused trip is a huge concern......if true is an important clue.

Maybe the water in coming in the main panel ( service entrance at the meter). Going undetected.......
Is the service panel outside or inside the home ?
Power coming in to the panel from a pole or under ground ?

Is the breaker that’s tripping on the top or bottom of the panel ? Is this the only circuit that’s tripping ?

If you have the skills and knowledge........pull the panel cover looking for water stains, rust, corrosion etc.

 

[Bert_]

No way for an outlet to have a fault like you mentioned.

I beg to differ. I have had at least a couple outlets get enough dirt and **** carried in by water that the whole mess became conductive. It would usually trip when it got wet.

 

[2Busy]

Home was built in ‘97 and electrical is original. This is an upstairs panel, appears to be a Siemens. Can’t see from the breakers what brand they are and I’m probably not comfortable or capable enough to be opening up the box to find out. Tried to attach pics so hopefully those help. The problem circuit is on breaker is #10 (right side, 4th slot from the bottom).

Next step, I think I’ll go with the suggestion of disconnecting the run after the first outlet and seeing if it trips after that. One newbie question—if I’m reading correctly, the panel says it’s rated for 125 amps but when I add up the capacity of all the breakers in there they total 275. Is that a problem? Not familiar with how that’s supposed to work.

Thanks to everyone offering their advice here, much appreciated!

 

[2Busy]

Pics attached this time

 

[Mike Folks]

Unfortunately,water travels, the suspected nail may be a considerable distance from water entry....

 

[wyliesdiesels]

Adding up all the breakers means nothing because of diversity of load.

You could have hundreds of amps worth of breakers but only have a 30a continuous lod.

 

[ddawg16]

Getting back to basics.....

Non of the breakers in that panel look like GFCI breakers. So, if you are tripping a breaker in the panel, it's current fault, not a ground fault.

You 'could' have a bad breaker. An easy way to tell....plug in an iron and turn it on. That is going to be about a 12-15A load depending on the iron. If no trip, then the breaker is good.

And since the issue only seems to come up when it rains....this means you have 2 issues....water is getting in....and something is causing a short when it rains.

I'm inclined to think when the wood gets wet, it swells just enough to push a wire against another wire. Finding the culprit is not going to be fun. If it was me, I'd examine an outlet close to the window. Pull it out and have a look at it. Look for any indication of water.

You should also know which outlets are affected by that one breaker.

If it was me, I'd find the outlet in the middle of the string and remove the wires going to the down leg series of outlets. Then wait for the next heavy rain. If it trips, you know the issue is between that outlet and the box. Divide in half again....repeat. This will help you narrow it down to a section so your not having to tear out a whole wall.

This will also tell you the most likely location of the water leak.

 

[SGKent]

couple things to consider

1) was the breaker tripping before the roof leak was fixed.

2) did insurance cover any of the roof repairs.

 

[2Busy]

Appreciate all the advice guys. Wylie, thanks for the explanation about continuous load. ddawg and SGKent, to your questions, if there is currently a water issue I already generally know where I’m going to find it. There are 4 outlets strung across an upstairs bedroom wall amongst 3 window dormers (doghouses as we call them here). I’ve been fighting a bad flashing job around those doghouses for several years. The one that has leaked in the past has been re-flashed and I’ve seen no signs of leaking since. Previous leaks have run into a porch ceiling and dripped down the outside front of the house. I haven’t seen any of that since the last fix about a year ago. My suspicion is that one of the unfixed doghouses is now leaking but not enough to drip down the wall, however it must not be enough water to be causing a problem with the circuit. The suspected area happens to be the end of this circuit so I’m going to disconnect the last two outlets and see what happens. We’re expecting rain this week so it’ll be a good time to test.

Sounds like very soon it’s going to be time to just call my roofer and have those last doghouses flashed. But after I deal with the water, there’s still the question of why the water was causing a trip in the first place. Sounds like I won’t have this totally dealt with until I get behind the wall once I’m sure where the problem is and replace the romex if I find a problem nail, staple, etc. Stay tuned, I’ll let you know what I find out after this week’s rain.