Temporary repair of RMC

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mark32

Senior Member
Location
Currently in NJ
A customer has, on rare occasions, water trickle into his main panel via the conduit that feeds the panel. The RMC leaves the meter and runs down the wall and just as it begins to turn a 90, it goes underground. I didn't have time to dig around the pipe (I was there for other tasks), but I assume that there must be a small hole rotted through the pipe, underground, allowing some water in when they experience heavy rains. We'd like to just do a temp fix for now (The RMC enters the back of the panel at the very bottom so water will not come in contact with the buss or breakers) and replace the RMC in the near future, but how? I was thinking about squeezing a tube of RTV at the hole's location and then wrap the pipe with some sort of wrap. I thought there was a metal fiber like wrap that would turn to a steel like material once it cures, I don't know. Any suggestions?
 

kwired

Electron manager
Location
NE Nebraska
You need to know if you have leakage through the pipe or through the wall penetration.

If just a minor amount of leakage it may just be condensation forming in the raceway and then running down, some duct seal in the end of the raceway won't completely stop condensation but can reduce how much occurs.

Wall penetrations can be difficult to ensure will remain sealed over time. A careful look at landscape and drainage can help though, water that wants to pool up near the structure is going to have higher risk of penetrating somewhere.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
RTV, although waterproof when cured, is not likely to make a good seal to a wet pipe. Can you get the outside of the RMC thoroughly dry and keep it that way until the RTV has cured (about 24 hours?).
Or you can use a patching method that is designed to harden and adhere underwater.

Possibly http://www.acehardware.com/product/index.jsp?productId=21209366
or maybe one which is not specifically rated for steel: http://www.pondbiz.com/home/pb4/pag...oYwGuC41fX2ljsOpbr_GdW-vDeYSsQEkAAaAvhy8P8HAQ
Or underwater adhering epoxy such as this product: http://www.amazon.com/J-B-Weld-8277-WaterWeld-Underwater/dp/B000BRQ0TW
I have used products like the latter for repairing pinhole leaks in drain pipes with good results.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
A customer has, on rare occasions, water trickle into his main panel via the conduit that feeds the panel. The RMC leaves the meter and runs down the wall and just as it begins to turn a 90, it goes underground. I didn't have time to dig around the pipe (I was there for other tasks), but I assume that there must be a small hole rotted through the pipe, underground, allowing some water in when they experience heavy rains. We'd like to just do a temp fix for now (The RMC enters the back of the panel at the very bottom so water will not come in contact with the buss or breakers) and replace the RMC in the near future, but how? I was thinking about squeezing a tube of RTV at the hole's location and then wrap the pipe with some sort of wrap. I thought there was a metal fiber like wrap that would turn to a steel like material once it cures, I don't know. Any suggestions?

this assumption is based on the water entering thru the conduit, not wicking thru
on the outside.

http://www.polywater.com/ductseal.html

when i did sealant, i put a 1/2" clear tube with a stopcock on the end of it thru
the seal, and sealed it like a wire. then, i can drain any water that is standing in
the pipe. it's never been necessary. after the rain subsides, the pipes would drain
back thru the hole where the water came in.

it's been six years, and all is well. before the repair, when it rained, it would fill
up a 50 gallon trash can with water in a day or two.

that stuff is awesome. iwire suggested it, and it kicks ass. it'll hold 22' of head pressure.

if you have external water wicking on the outside of the pipe, 3m 550 urethane will seal
it. if you have to, you can trowel it onto a surface to seal it. designed for sealing boat
hulls below the waterline.
 

mark32

Senior Member
Location
Currently in NJ
Thanks for the replies fellows. The water comes in from the raceway, not from the wall penetration, this is obvious when you look at. I do have some JB Weld putty that turns very hard once cured, like that Gold linked to. I prefer, however, the item fulthrotl is talking about as I won't even have to dig around outside in the frozen NJ dirt. fulthrotl, where did you get that product? I'm looking at the product here: http://www.70esolutions.com/fst-mini-foam-duct-sealant-single-kit/?gclid=CITgqPeh-MoCFUIfhgodPsEM1Q
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Since better alternatives have been posted, I hope you are not going down the RTV path.

But if you are still considering it, a huge caution: most RTV materials give off acetic acid (they smell like vinegar) when they cure. These fumes can cause significant corrosion on electrical equipment. There are RTV materials specifically made for potting electronics, but you must select them specifically.

-Jon
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
What makes you think there is a hole in the conduit? Are there any couplings? Conduit couplings have straight threads and they leak.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Thank you for the tip on the RTV Winnie, I'll keep that info in mind. Don, while I didn't unearth the conduit, I don't suspect there are any fittings present as it's such a short a short run, anything is possible though right.

I looked at the Polywater product but went with this instead as it was less expensive:

http://www.chemque.com/pages.php?page=Q-Pak_Expanding_Foam

the polywater i got from a wholesale house in LA, it's not widely carried...

however, amazon has it for a buck and a quarter a kit.... looks like what you found will work in a similar fashion.

http://www.amazon.com/American-Poly...1-fkmr0&keywords=Polywater®+FST™+Duct+Sealant
 
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