Laying underground cables - how do I seal the empty conduit coming out of the house?

Hello,
we are currently planning the garden, and as part of that we want to lay an underground cable at the back of the garden. For this, a conduit (a regular corrugated pipe) is installed from the fuse box in the basement through the basement wall to the outside. The corrugated pipe ends about 50cm outside the basement wall.

If I now install an underground cable, I would prefer not to just lay it directly in the ground, but also protected with a corrugated pipe, as is recommended everywhere.

How do I now extend the corrugated pipe from the basement wall so that it is waterproof? Are there waterproof sleeves, sealants, or similar for this?

Alternatively, it would also be conceivable to seal the corrugated pipe waterproof (silicone? well foam?) after pulling through the underground cable and simply lay a second corrugated pipe without a "connector" to the first one through the garden.

How is this usually done? Surprisingly, I can’t find anything about this online...

What is supposed to happen if it simply lies in the ground? Waterproofing is even more unnecessary. A pipe as additional mechanical protection is more than enough. But yes, waterproofing would also be possible. There are shrink sleeves that you can shrink accordingly over the respective pipes... In my opinion, however, unnecessary

With the cable in the garden, it is actually mainly about mechanical protection. Waterproof is especially important to me for the [conduit] that goes through the basement wall to the control cabinet. I don’t want water to penetrate into the control cabinet during heavy rain.

If you punch holes on the underside, any water that has entered should also drain out again.

I think the heat shrink tubing is good. How long should the underground cable be? It should definitely be laid below the frost line, and a warning tape for the route can’t hurt either.

Hi,

I had similar thoughts 20 years ago, back then it was about an underground cable to the garage.
You consider all sorts of things; I led the empty conduits into a Tupperware box and sealed the entries with acrylic and tape. It was actually completely unnecessary.

However, if you seal anything with silicone on live parts, you should make sure that the silicone is not "acetic crosslinking."
Otherwise, you create nice short circuits because it is electrically conductive.
Unfortunately, I know this from personal experience :mad:.

Regards, Olli