Insulating unheated attic - electrical installations

What surprises me about the question and discussion is that the attic is not insulated but has thermal insulation glazing. Are you building new? What does your energy consultant say? For us, the KfW calculation was done on the building envelope, including the attic/roof space. The collar beam is insulated, but that wouldn't even be necessary. For us, the entire roof is insulated up to the last tile and within the vapor barrier... The pipes can definitely be laid in the attic (also in your case). What is important is a good, complete, and professional sealing in the area of the vapor retarder/barrier.

The attic is not intended as living space, otherwise it would also need heating = more expensive therefore it is not insulated either

solid windows are triple glazed simply because everything else is triple glazed too, at least it doesn’t hurt, right?

and I want to insulate the attic so that you can spend time there occasionally, I myself used to have my LEGO mess corner there for example and didn’t freeze in the winter because despite the new building it was insulated afterwards

in summary I have taken the following with me:

- 100% airtightness is not necessary, but close to it
- so running a cable through the foil or staples are less of a problem
- the "balloon effect" (warm overpressure air finds the one hole in the vapor barrier and moisture then condenses there) can be neglected with smaller holes
- the vapor barrier must also work/be sealed horizontally at floor level (of the attic), i.e. be closed with the lower vapor barrier so that no moisture can pass horizontally through the OSB boards to the outside beyond the upper vapor barrier
- the insulation under the OSB boards (from the attic downward not protected by a vapor foil) is not affected by moisture