How to seal cable installation on an exterior wall?

let the builder do it for warranty reasons. If you make a mistake there, it can destroy the wall (and yes, such things do happen) (...)

I want to remind you of this once again. Yes, it's annoying. But take it seriously. If in 5 years the insulation on the wall rots and the expert finds out that you yourself laid cables outside and did not seal them properly...

I work in special plant construction. What do you think we look for first when there is damage at the customer's site? Exactly, external fault due to tampering with our system by the customer. Then we don't pay anything...

Oh cool, I know those parts for the roof when you have a cable or pipe exit there. That means you could also use them for the exterior wall. (Example Poroton hollow brick. The weak point at the cable exit between mineral wool and exterior plaster remains though

No, not necessarily. For example, if you use the fleece-butyl collars from Eisedicht, they can be installed directly on your insulation and then plastered over. This way, the cable can be sealed airtight exactly at the exit point.

If you really want, you can of course also install an aluminum-butyl collar behind on the wall and then insulate over it – this way you have double protection.

(...) this way you have a double safeguard.

And if you don't do it properly because you don't know better... then you have nothing at all :D

So I asked my energy consultant. You actually only need the parts if you go through the vapor barrier. With a solid wall, that would not be necessary.

So I asked my energy consultant. You actually only need the parts if you go through the vapor barrier. With a solid wall, that would not be necessary.

Is your energy consultant a civil engineer? Or a retrained cook who could no longer work in his job?

So I asked my energy consultant. You only really need the parts if you go through the vapor barrier. With a solid wall, that wouldn’t be necessary.

Your wall is only partially solid. Behind the plaster there is an 18cm ETICS of mineral wool (and an additional plaster base coat in front of it?).
It rots away when wet. So it must be sealed. Don’t just ask an energy consultant whose certificate is done in three afternoons (i.e. not that all energy consultants have no clue). But here, ask the responsible house builder, who guarantees the house. If he gives his OK (in writing) for your planned penetration, then all is good.
And almost every wall has a vapor barrier of some material anyway. Or am I mistaken here?