Electrical installation: 3 experts - 3 opinions

Toaster, kettle, hairdryer, etc...
How you can save a few euros 50 on cables when you're spending almost a million on the house, I can't understand. But then again, every technical gadget with KNX etc...

The reason is of course not savings (that you don't realize this yourself...), but the problems that arise from using 2.5mm when clamping. In a box with continuous KNX, 1Wire cables, sensors and sockets, it is very tight despite deep or double boxes! That alone is the reason for 1.5mm.

(You don't need a kettle, hairdryer and toaster are only on briefly and don't draw that much either)

Well, I only lay the cables. I leave the connection of the outlets and the fuse box to others.

Pulling cables is a helper or apprentice job. However, helpers or apprentices usually do not do it alone, but are accompanied by a journeyman who is already familiar with the installation regulations. In modern installations using empty conduits, there should not be any direct proximity between cables and insulation (or whatever else requires spacing).

I wonder how often something like this happens, where everything in a room is on at the same time and you then reach over 2500 W.

Basically, relatively rare, but you can also reach it fairly quickly.

In the children's room, the gaming PC runs at medium load (500W), the radio is on, and a desk lamp, network switch, a few devices on standby, phone charging cable, PS3, etc. etc. .... let's ignore those. The mother comes in with the vacuum cleaner (800 W) and the son starts a print job on the 120 euro 0815 laser printer. 10 seconds warm-up phase (1,000W)

In total, you’re easily at around 2,300W for a moment without base load and other consumers.

So I don’t necessarily find such a scenario unrealistic for a 16-year-old in a youth room. And yes, of course, there are solutions for that too.

for a moment

Please study the basics of electrical engineering "for a moment" is exactly the right keyword!!! There is a difference between "for a moment" and 3 hours of continuous load.

At the topping-out ceremony, I had to improvise a bit (it was cold) and "blocked" a 16A fuse in the construction site power distributor. Then there were sometimes 2x 3500 watt heaters connected. It ran for about 4 hours. Surely the cable was quite hot...BUT...even after a few minutes nothing would have happened...or at least it wouldn't have gotten very warm.

The reason is of course not savings (that you don’t figure out yourself..), but the problems that arise from using 2.5mm when clamping. In a box with continuous KNX, 1Wire cable, sensor, and socket, it is very tight despite a deep or double box! That alone is the reason for 1.5mm

(No need for a kettle, hairdryer and toaster are only on briefly and don’t draw that much)

Oh yes, I have laid 2.5 everywhere and curse every time anew when I want to wire something in the deep box now. [emoji3]

Oh yes, I used 2.5 everywhere and curse every time anew when I want to wire something in the deep box now. [emoji3]

Sounds ironic... as said, it's not about 2x incoming 5x2.5 but 2x 5.25 + KNX + 1Wire + this and that (reed e.g. at windows)..