# Leaking Conduit



## Bubbles (Sep 27, 2007)

We have a nice small flood of water coming out of an old 1970 4" conduits in a CT Cabinet (4ft below ground level) in a basement (Pretty crammed with original duct seal as well). The owner can't really afford to solve the problem (maybe) 5-10K excavating. So, were going to see hopefully if the water is coming down across street down the start of conduit at utility pole and if so plug up. I tend to think it's going to be a loose connector 3' underground. My question is, other than Duct Seal is there any good tight water sealing compounds we are allowed to use around the conductors where they enter the CT that will not affect the insulation. Essentially corking it. 

thanks for any input


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## JohnJ0906 (Jan 7, 2007)

Silicone, maybe? I would think it won't damage the insulation. (but I am not sure about that)


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## rustyjames (Aug 28, 2008)

I would go with polyurethane, that stuff is used on automotive windshield installation and the trim that fills the opening is typically plastic. It also likes moisture, in fact wetting it is often done to accelerate curing.


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## TxElectrician (May 21, 2008)

Can you turn off power, pack conduits with fiber, and fill with chico? 

If it is a good enough filler to block fumes I would expect it to block water. I do not know if this would be compliant with the code.


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## 480sparky (Feb 1, 2009)

I doubt very much any fix you do will be permanent. Conductors have a habit of moving, and any seal around them you manage to make will eventually fail, especially if the water has any amount of pressure.


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## Softy (Jul 26, 2009)

Isn't there a loop and hook at the service cable down from the pole? I think problem is in the ground. If the inspector find out HO will have to gut the whole system.


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## thom (Nov 3, 2006)

I wouldn't do a patch job. If you think the issue is underground, it probably is. Any "patch" you do could make you responsible for the failure of the system. You know that if/when there is a failure a year or two down the road, the owner's first thought will be "we paid this electrician to fix it".


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## macmikeman (Sep 12, 2005)

Might not make it past the UL police that lurk on forums but try expanding foam to seal the duct, with some duct seal after at the very top.


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## Softy (Jul 26, 2009)

macmikeman said:


> Might not make it past the UL police that lurk on forums but try expanding foam to seal the duct, with some duct seal after at the very top.


Forum police is the least I'll be worrying about. In my neck of the wood. Negligently repair of service entrance wires can be costly. Let just say you'll want to move to China when POCO, city and state pull a plug on you. I honestly can't believed you telling another electrician to use expanding foam. The bottle even recommended not to use on wiring let alone entrance wires. If you were to comply with NEC then water logged wiring need to be RRR. In some cases you can use Nitrogen gas but not likely with service entrance.


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## macmikeman (Sep 12, 2005)

Softy said:


> I honestly can't believed you telling another electrician to use expanding foam. The bottle even recommended not to use on wiring let alone entrance wires. If you were to comply with NEC then water logged wiring need to be RRR. In some cases you can use Nitrogen gas but not likely with service entrance.


Oh really? Care to give some facts Softy? hint: Start with wet location listed conductors or direct burial cables used as service entrance conductors . Those get wet all the time and are not required by the NEC to replace when they do.


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## Static Design (Nov 30, 2008)

closed cell spray foam /thread.


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## S Winklepleck (Jul 31, 2009)

You're not supposed to use expanding foam? Don't most electricians seal up their holes through the top plates, sill plates, etc after they run their wires with expanding foam? Come to think of it, I've met an inspector for a wiring and rough frame inspection on a bathroom job we did and he TOLD me to put expanding foam in the holes.


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## Softy (Jul 26, 2009)

macmikeman said:


> Oh really? Care to give some facts Softy? hint: Start with wet location listed conductors or direct burial cables used as service entrance conductors . Those get wet all the time and are not required by the NEC to replace when they do./quote]
> 
> So true but we aren't talking about direct buried nor wiring in the water. We're talking about main service entrance wiring that run from POCO/meter underground using PVC conduit. This in itself has it own interpretation and therefore manufacturer and city ordinances and in some case NEC must be complied. FACT: water logged can cause acid and breakdown insulation. Lack of thermal dissipation because of no air movement inside conduit, THHN breakdown at about 90 C. Water is 2 part Hydrogen and 1 part Oxygen. Arcing between 2 wiring will cause Hydrogen build up and eventually cause explosion. This is why when plumb the conduit it's very important that you use lots of glue so no water can get in.
> 
> As for foam insulation. I was referring to "foam in conduit" NOT framing nor some bathroom repair job. I didn't elaborate but was hoping you would know that since you're an electrician. Though I sure love to see you use it for your customer, lol.


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## Bubbles (Sep 27, 2007)

*Water Leak*

Good Stuff here. 1 correction and comment. It's 4" Rigid conduit. Owner will not pay 10k to excavate and fix. He specifically says patch it. And he is paying the bill...so....Still not sure what method is best on here yet??


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## Softy (Jul 26, 2009)

Not sure either. Water might run itself dry since HO box is below ground. It's really a hit or miss. See if you can purge with compressed air. May be just do it but no paper work:laughing:
I would check with city ordinance see what's required but don't tell them about your customer...there's a local code specifically for service entrance and your city should be able to provide that.


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## 480sparky (Feb 1, 2009)

Bubbles said:


> Good Stuff here. 1 correction and comment. It's 4" Rigid conduit. Owner will not pay 10k to excavate and fix. He specifically says patch it. And he is paying the bill...so....Still not sure what method is best on here yet??


If a $200 'patch' will do the same as a $10,000 'fix', then why do the 'fix'?

Simple. A 'patch' will only fail. Fix it, or forget it.


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## Softy (Jul 26, 2009)

Local code will give you the final solution but for me I'm representing a $30 millions+ per year company. Quick fix is a no-no. Insurance will eat us alive. BTW, direct buried HV and rigid conduit is not even allowed in California. We don't use it anyway.


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## Inner10 (Mar 12, 2009)

> Arcing between 2 wiring will cause Hydrogen build up and eventually cause explosion.


Has this ever happened?

I've never been successful sealing around more then one wire, its like peeing into the wind. I did it onece when the designer wanted wires hidden in a rooftop flower box, it leaked. Then they had the roofing contractor do a "proper repair" and next spring it leaked.

Spray foam can be dangerous stuff it it doesn't have room to expand it begins damaging things (I saw it buckel a metal door). 

I'd duct tape my wet/dry vac to the pannel end as best I could, then use my blower at the service end and dry it out as best as possible. Then inspect for the leak, look for a place that water would collect and be funneled into it takes the path of least resistance. Onece located use a hair dryer to dry the area and pump it full of silicone.


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## Softy (Jul 26, 2009)

You got the code requirement yet? If not what's your customer state/city/county? May be I can call your local planner from here. Might take me few day I'm in the field 300mi from home.


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## Bubbles (Sep 27, 2007)

*leaking*

As it turns out, I finally got to witness the leaking. It was coming from the outer diameter of the conduit where it enters into the basement. Didn't see anything coming out of the conduit and it rained 4 inches the other day. The whole place was flooding all over different parts of basement. When they fix all that and rechannel the water the problem should be over. We can just seal around the conduit now. If it's an existing problem I thought anything pre 78' they cant' force you to do anything about it code wise, unless it's considered a major hazard. Around here that's the key word "existing" 

Thanks for all the input


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