Fault arc circuit breaker in prefab house

We also resisted, the house construction company wanted almost €4,000. The electrician told me during the installation that his company almost never installs these switches... somehow that says something to me as well...

The switches are not per RCD, but per fuse/circuit [...]

As I have now learned, both are correct! There are AFDDs in four (roughly two with sub-variants) versions:

1/2: As an "add-on" solution to normal circuit breakers and RCDs, these then control their respective neighbor via a shaft

3/4: As combination switches. Then in combination with only CB as well as with a RCD/CB

Regarding Schwörerhaus, with whom we are building: Approximately 27 AFDDs (fire protection switches) are actually installed. This number varies slightly depending on equipment but is roughly accurate.
This refutes my assumption that only as many switches as RCDs are installed, at least concerning Schwörerhaus. At least now I know what to expect and won’t later think I paid for 27 but only got 7.

Funny that there is now coincidentally a thread about this. With us, these things were simply installed without being charged separately anywhere. They also were not listed in the cost evaluation. I had to google first what kind of parts they actually are - I had never seen them before either. But I won’t complain, when I read what other house providers charge extra for them..

Unfortunately, these are not even outrageously inflated prices from the home construction companies. The switches are very expensive to purchase - until a few months ago, there was only 1 manufacturer. Installation and a larger box cost.

Great that they were simply installed.

Funny that there happens to be a thread about this now. At our place, the things were simply installed [...]

Could you send me a picture of your distribution box?

So in my case, the house builder covered the additional costs after I was able to show that the standard is just a standard and not a law... However, no electrician was found who would still install it without [einbaut].