Sealing cable conduit, with what?

[Marcus Hennix]

Building a house is truly an endless series of difficult-to-solve problems, and now we've encountered yet another one. Our utility cabinet is about 1.5-2 meters above our foundation, and our electrician has informed us that the protective cable conduit running from the utility cabinet underground into the house could act as a siphon if there are leaks due to the height difference, which neither I nor the excavator operator considered when the work was done. The problem is compounded by the fact that the excavation company that carried out the work has laid these cable conduits incredibly deep, they more or less dive straight down from the utility cabinet and into the foundation and are situated at several meters' depth, making it very cumbersome to cut the conduit down in the ground. My thought was whether it is possible to cast a waterproof enclosure around the electrical cable and what should be used in such a case? Epoxy? Bitumen-based? Bentonite clay? Any other tips?

 

[1977bjorn]

I pushed expanding foam into my pipes. It became tight.

 

[OlaMalmö]

Building a house is truly an endless sequence of difficult problems and now I've realized another one. Our ground cabinet is located about 1.5-2 meters above our foundation and our electrician informed us that the conduit running from the ground cabinet underground into the house can act as a siphon if there are leaks in it due to the height difference, which neither I nor the excavator operator thought about when the work was performed. The problem is that the excavation company that carried out the project has laid these conduits incredibly deep, they more or less dive straight down from the ground cabinet and into the house foundation and lie at several meters depth, which makes it very complicated to cut the pipe down in the ground. My thought then was whether it is possible to cast a waterproof enclosure around the electric cable and what to use in such a case? Epoxy? Bitumen-based? Bentonite clay? Other tips?

Which solution did you go with? I have two conduits that, like yours, are way too deep to dig up and cut. Now they've cracked and every time it rains, water runs into the basement.

 

[Marcus Hennix]

What solution did you go for? I have two cable protection pipes that, like yours, are way too deep to dig up and cut. Now they've cracked, and every time it rains, water flows into the basement.

I ended up puncturing the pipe as far down as I could reach from inside the house and then filled it with foam sealant via a hose. Foam sealant isn't airtight, but it should at least dampen the flow. As a final touch, I cast a mirror of epoxy on top as a cover about 20 cm below the bottom level of the edge beam. The idea was that the holes I made still terminate just below the drainage, so any water should hopefully find its way there. I do plan to dig in from the top at the ground cabinet if problems arise, but that won't be a pleasant job. I'll have to go down about 2 meters around the pipe to get below the footing's level and then drain around everything to finally lead out to a ditch so that a water column over the gravel bed can't occur. What do the levels look like around your house/ground cabinet?

 

[OlaMalmö]

I have two cable conduits running from the basement to a small garden house at the other end of the garden. Probably 1.5 m below ground level and the pipes unfortunately run under a large extension and a deck, so digging them up is unfortunately not an option for me. I have considered if it would be possible to make holes in the pipes so that the drainage could take care of the water, as you did, but haven't come up with a good idea for how I could manage that. What did you use?

 

[Marcus Hennix]

I have two cable networks running from the basement to a small garden house at the other end of the garden. Maybe 1.5 m below ground level and the pipes unfortunately run under a large extension and a deck, so digging them up is unfortunately not an option for me. I've been considering whether it would be possible to make holes in the pipes so that the drainage could take care of the water, as you've done, but I haven't come up with a good idea on how I would accomplish that. What did you use?

Since I didn't need to go so far underground (about 30 cm), I was able to dig around the pipe on the outside and then carefully make a hole with a knife. However, I also considered how one could puncture a couple of meters inside the pipe but didn't come up with a realistic solution. Mechanically cutting a hole feels almost impossible so far in and burning a hole with some kind of hot wire seems very risky as you'd likely melt the electrical cable's protective sheath.