Conduits in empty pipes in screed

1.) Is it allowed to install a flat cable in an empty conduit within the screed?

2.) Is it allowed to install a flat cable (without an empty conduit) in a chase within a gypsum board wall?

3.) Is it allowed to install a flat cable (without an empty conduit) on a Ytong wall (under the plaster)?

I would generally not install flat cables anymore, but I still have about 50 m left and would like to use them up completely.

Regards!

I would generally not install any more [Stegleitung] at all, however, I still have about 50 m and would like to use it up completely.

Because of 50 meters (so about 20 euros) you want to use something you actually don't want to use just because it’s there?

Sounds plausible what you say......when I think about it carefully it's 100m, instead of 50 m.

But I'm just interested too.....I'm an electrician by profession, but haven't worked in the job for about 20 years. Back then we worked a lot with [Stegleitungen]......today they are probably almost extinct....

Stegleitungen may be installed according to DIN VDE 0100-520 in dry rooms in or under plaster on non-combustible substrates. This would only apply to your installation method 3.). Google the DIN for more details.