Wiring sockets, switches

The device sockets, i.e. the sockets for devices from 2kW where you can be sure that they really have to carry up to 16A for a longer period, were all executed as 2.5² here with me by the way. There seems to be something to these recommendations. You also may not fuse the 2 loaded conductors with 15.5A with 16A. But RotorMotor knows everything better anyway, and my electrician probably just had to get rid of 2.5² before it starts to rust ;) or to mold?

… But RotorMotor knows everything anyway and my electrician probably only had to get rid of 2.5² before it starts to rust ;) or mold?

Fortunately, our electrician didn’t have to get rid of any unnecessary 2.5mm2;-). That’s why we have slim 5x1.5mm2 cables everywhere except in the kitchen.

In my place, the entire house wiring is 2.5mm², fused with 16A, and the earth conductor to the garage is 5x16. 1.5mm² was not installed anywhere, not even to the lights. There was never any inquiry about it, the electrician always does it that way. It wasn’t expensive either.

Well, the "new" standard states that only 13A is allowed for thermally insulated timber frame walls/ceilings with 1.5mm². When installed under plaster and/or in conduit, 16A is still permitted if the cable length does not exceed (I believe) 16m.

That's the theory for now; we all know the reports of apartment fires that spread across Germany when the standard was lowered from 16A to 13A because the cables suddenly were no longer "sufficient" ;).

Personally, I am a fan of 5x2.5mm² and 4-6mm² (depending on the cable length to the kitchen) in the house. Additionally, every room should have its own RCD (not just at least 2 as required by the standard). Residual current breakers for fire protection are also worth considering if you still have some extra money for electrical work ;)

There is so much margin built into all these standards and formulas that 1.5mm² can handle more than 16A (the problem is more likely the sockets, for example).

The classic. Industrial electricians who think "I can lay that little cable myself" and then quickly realize "uh what do I have to consider? And how do I even do that?"

Better leave it, wait for the master electrician. Otherwise you'll end up tearing everything out again.

A look into the reference book proves him right, by the way. In thermally insulated walls laid in installation conduits, a 3x1.5 NYM cable may only carry 13 A, so fuse protection with 10A. And then there’s also the reduction factor because in midsummer the wall temperature can sometimes be above 30°C.

Well, the "classic" has installed quite a few houses already. And they were approved benevolently. Now the last one was 5-7 years ago and this time it’s the first timber frame wall with insulation material. As you can see, I already suspected that things might be borderline different here. And again: We can’t wait for the master electrician. It has to go on. You surely don’t have to tear it out, at most lower the fuse rating. What’s odd is that the house construction company supplied everything with 1.5mm² and not a single 10/13A circuit breaker is included. By the way, there’s some 2.5mm² cable for the kitchen installation included.

...The only strange thing is that the house construction company delivered everything in 1.5mm² and there isn’t a single 10/13A circuit breaker included.
By the way, there is also a little 2.5mm² for the kitchen installation.

As could be seen from some comments, there is nothing unusual about the delivery of 1.5mm² material. I suspect that this is how it is done by the majority. 1.5mm² for sockets, 2.5mm² for appliances in the kitchen such as stove, oven, refrigerator, etc.