Electrical installation - is everything okay with it?

So far, I have had to replace at least two different ones... I think, I didn't note it down, unfortunately. Are there any inspectors or similar for electrical installations?

Google: Expert in Electrical Engineering

Or: Take the notes here from the thread (loose terminals, loose wires, too many wires in one switch, fuse too small) and write a defect notice to the installer. By registered mail and with a deadline for rectification within 10 working days, for example.

Apparently, this is quite a mess. As usual, the matter has two aspects:

1.) The technical aspect
You can get someone who knows about this. It can be a well-known master electrician, just preferably not the brother-in-law’s friend who likes to tinker in his spare time (unless he is a master electrician). Or even better, an official, appointed expert (Yellow Pages, Google, Chamber of Crafts, professional associations, ...).

2.) The legal aspect
Unfortunately, it is possible to lose your claims for defect remediation due to formal errors! Then you are right but don’t get it and are stuck with the damage! Unbelievable for the naive layperson, but that’s how it is. Therefore, it is important to clearly know the legal situation as well (Who commissioned whom? What was agreed? Which law applied? Has the service already been accepted?) and to report defects properly and within the deadline. If you cannot answer the questions, get advice from a specialist lawyer for construction law (Yellow Pages, Google, Bar Association, ...).

So I have approached the developer again and listed for him everything that is (at least) not in order. Thank you very much for your feedback on this. But from a safety perspective, I don't have to worry that all of this will "fail" at some point, right? I only know control cabinets from industry, and there it simply looks different...

Well, it depends. If the wrong fuses are already used, what can one think about the rest?

You are right again... but if the measurement results were good, that's already positive, isn't it?