Arc Fault breakers producing water.

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PhantomElectric

Member
Location
Owensboro, KY, USA
ok, first this is my first time posting and it's nice to meet you all.

quick background. electrician since 2000 , current own and operate an electrical contracting business and a tech company. primarily residential work with some light commercial.

a customer of ours had an arc fault breaker dead shorting (melodramatic as arc faults dead short). we are currently on the 2014 code, but the house was built 2 years ago when we were on the 2011 code. all 15 amp circuits are arc fault with the dining being the sole 20a arc fault. went to change the breaker out and noticed it was soaked. shut off the main and started pulling breakers in the 200a square d homeline panel. these breakers are the pigtails since it was put in prior to the homelines going to full length neutral bars. about 90% of the arc faults in the panel were soaked, none of the other breakers. it's like they are producing water. panel is in a storage room of a walk out basement, on a stud wall, open drywall, with 1/4" between the panel and the concrete wall. 15a breakers on the right were mostly all soaked and the sole 20a on the left side of panel was the only thing wet on that side.

so let's get the obvious out of the way. there is zero water coming from the mains, any wires leading into the panel, there are no water marks around the bottom or back or top of panel. there are no plumbing pipes within 10 feet of panel and the room, while not heated and cooled, stays a pretty constant temperature as the basement great room next to it. water is absolutely, 100%, without a shadow of a doubt leaking, penetrating, siphoning, leeching, dripping, spraying on the panel. at first i thought condensation, but that would be backwards. cold things get wet in hot weather, not warmer things getting wet in colder weather. the rest of the panel, excluding the arc faults, is completely dry down to the cobwebs and drywall dust. the bottom, top and back of panel is dry.

i have emailed square d tonight and should hear from them tomorrow; if not i'll just call at lunch. wanted to see if anyone here has seen this or has an answer. saw another 2012 post on here with the same problem also 2 years in. it was a dead post and saw no advantage to not making a new one. that guy got brushed off with jokes like he was just not catching a water leak or put in wet breakers to begin with. anyway, thanks ahead of time for any help.
 
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JFletcher

Senior Member
Location
Williamsburg, VA
Welcome to the forum. I assume the previous thread you mentioned was this one?

http://forums.mikeholt.com/showthread.php?t=142160

Are you sure it's water and not something else?

The panel is in the basement. If it (the basement) is humid and reaches a temperature higher than the panel, condensation could occur on the inside, tho why it would only be on AFCI breakers is beyond me.

"cold things get wet in hot weather"

the panel being mounted on a block wall has a rather large heat sink (even with the air gap), iow the panel will be closer to the wall temp than the air temp, especially if there is little air circulation.

I dont know the cause of the problem however I would try a small fan aimed at the panel to keep it close to ambient temperature to prevent condensation.

Pictures?
 
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John120/240

Senior Member
Location
Olathe, Kansas
Can't imagine why Arc Fault breakers would be any wetter than other breakers . You state that there is NO sign of water infiltration so I am stumped. One time underground service, the transformer was on a rise higher than the meter. The conduit would fill with water & soak the meter & panel.
 
Little Bill

Little Bill

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Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
PhantomElectric said:
water is absolutely, 100%, without a shadow of a doubt leaking, penetrating, siphoning, leeching, dripping, spraying on the panel. at first i thought
Click to expand...

I hope you just made a mistake and left out "not", as in not leaking, etc..............

AFCI breakers can get hot and some suggest spacing them apart in the panel.
That would explain how condensation could be on them with the breakers being hot in a cool basement. It doesn't however explain why at least some moisture is not found on the other breakers or somewhere in the panel.

Let us know what Square D says.

Welcome to the forum!
 
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PhantomElectric

Member
Location
Owensboro, KY, USA
Called square d and they are at a loss. Going to rma the arc faults and send them back so they can inspect. The basement I was referring to is a finished temp controlled basement in a very nice home; not unfinshed cooler basement. All wire is Romex excluding SE and then for generator hookup. I will get some picks of it tonight. All of the romex's cardboard that wraps the ground wire is also dry.
 
mopowr steve

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I haven't yet spent $35 just to bust one open and check out the electronics inside but is there a chance it's di-electric oil from some kind of capacitor or mov inside that ruptured because of a high voltage or lightning strike?
Do they still operate?
 
mopowr steve

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I would lean towards water entering in fron SE cable. The condition may only present itself rarely enough that there is no visual signs of staining as to its source----yet. Since the OP said it's primarily on one side of the panel, without air circulation within the panel the water can lay there for a while.
Be interested to hear more on the findings.
 
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PhantomElectric

Member
Location
Owensboro, KY, USA
maybe some of the answer

maybe some of the answer

ok so square d is rma-ing the breakers with a "no questions asked" routine; kinda weird. cracked the LB open on the outside again in the daylight to take a closer look. the inside of the LB looks dry at first in the bottom, but up on the walls of the LB condensation is forming. the arc faults are the warmest breakers in the panel and the only ones that were wet. best we can tell the cold moist air was coming in to the panel and cooling things down quit a bit and the arc faults being warmer collected condensation. tonight we replaced all breakers and spray foamed the hole from the LB side and drilled some really small weep holes in the bottom of the LB. we cracked one of the arc faults open and didn't really find a lot of moisture, so it looks like it's just collecting on the outside.
 
G

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
One more time: Condensation collects on cold surfaces, not warm ones.
Unless there is an air flow pattern that directs even warmer moist air at the AFCIs and leaves the other breakers out of the airstream, the condensation will happen first and most on the cooler breakers.
 
mgookin

mgookin

Senior Member
Location
Fort Myers, FL
PhantomElectric said:
Called square d and they are at a loss. Going to rma the arc faults and send them back so they can inspect. The basement I was referring to is a finished temp controlled basement in a very nice home; not unfinshed cooler basement. All wire is Romex excluding SE and then for generator hookup. I will get some picks of it tonight. All of the romex's cardboard that wraps the ground wire is also dry.
Click to expand...

I understand you're saying "a finished temp controlled basement..." but can you give a little more detail?

Is there a 2x4 stud wall inside the block wall with a vapor barrier and the panel is flush mount such that the back of the panel is subject to the atmosphere which the face of the block is subject to?

FYI a block wall is going to condensate on the inside even with the best waterproofing on the outside, because of the temperature differential. I'm wondering if the same thing is being repeated with the face of the wall and a vapor barrier on a stud wall.

And are they willing to remove some baseboard to see if the drywall is wet at the bottom?

That was smart in choking off the incoming conduit. But where is the weep hole draining to? Maybe do the same at the other end of the conduit?

And contacting Square D was the right thing to do. Most people don't realize how accessible and willing to participate manufacturers are. It's in the manufacturer's interest to know these things.
 
mopowr steve

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
PhantomElectric said:
ok so square d is rma-ing the breakers with a "no questions asked" routine; kinda weird. cracked the LB open on the outside again in the daylight to take a closer look. the inside of the LB looks dry at first in the bottom, but up on the walls of the LB condensation is forming. the arc faults are the warmest breakers in the panel and the only ones that were wet. best we can tell the cold moist air was coming in to the panel and cooling things down quit a bit and the arc faults being warmer collected condensation. tonight we replaced all breakers and spray foamed the hole from the LB side and drilled some really small weep holes in the bottom of the LB. we cracked one of the arc faults open and didn't really find a lot of moisture, so it looks like it's just collecting on the outside.
Click to expand...

I am trying to imagine your service,
So do you have SEU cable inside of PVC conduit from meter to panel? And tell me if you have SEU or some other cable in PVC or not coming from top of meterbase up to attachment point or is it underground fed?

Many times what happens with SEU cable, is moisture can get into the jacket of SEU cable it will wick all the way down to panel, then follow one of the hot leads until it drips off either on top of the main breaker or right down onto either side of the panel's breakers.

Sealing the conduit was the right thing to do. Because of condensation and rodent damage. If not mistaken I believe it can be found in the NEC. It one of those codes that's overlooked quite a bit.
 
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