Electrical installation: 3 experts - 3 opinions

Hello everyone,

My wooden house is more or less finished, and I want to tackle the cable installation myself.
I will have the electrician from the developer show me where to lay the cables, which beams I am allowed to drill through, etc., but I will leave the fuse box, sockets, etc. to be done by professionals.

It already starts with the procurement of materials and the choice of cables.

- Expert 1 (architect and trained electrician): A 5x1.5 (with 13A fuse) supply line to each room and from there with 3x1.5 cables to lights and sockets. Reason: less material, smaller fuse box, less work

- Expert 2 (master electrician): 3x2.5 cable in every room for sockets and 3x1.5 in every room for lighting. Let sockets run on a 16A fuse. His reason: if the fuse of the socket blows, you still have light in the room, and the load capacity of the sockets increases.

- Expert 3 (master electrician): For himself, he would have taken the option of Expert 2. But he could also live with the option of Expert 1, but then with a 5x2.5 supply line and then 3x2.5 to sockets and 3x2.5 to lights.

My goal is of course also to reduce costs and work. Since I am dealing with each room separately, it will be difficult to overload a 1.5 cable with a 13A fuse. For that to happen, I would have to run a TV, 2000W vacuum cleaner, hairdryer, lights, and radio all at the same time in one room, right? Rather unlikely, isn’t it? My father also combined several rooms in the old house, and maybe every few years a fuse blew. Then you just go to the basement with a flashlight and switch it back on... done!

Of course, it is logical that large appliances have a separate circuit or that the stove has a thicker cable.

As a layman, I don’t see any need to have multiple fuses/circuits for each room.
But are there any experts here who have a different opinion?

Regards
Tito

Look, the topic was already discussed today at noon:

Definitely expert 2 if you want to do it according to the current state of technology. Nowadays, 3 x 2.5 is installed to sockets. This is not only related to what you connect at the back, but also to the cable length. Besides, in 5 years you might want to connect a heater or something else to such a socket.

Definitely professional 2 if you want to do it according to the current state of the art. Nowadays, 3 x 2.5 is laid to sockets. This is not only about what you connect at the back, but also about the length of the cable. Besides, in 5 years you might want to connect a heater or something else to such a socket.

Topic cable length: That's why with 1.5 cables you take a 13A fuse instead of a 16A one, right?

I wonder how often it happens that everything in a room is turned on at the same time and you exceed 2500 W.

Would you then have two fuses per room (1x socket + 1x light) or would you combine the lighting of several rooms?

Regardless of sense/nonsense, I also want to have network isolators in the children's rooms and bedrooms. So I would need two fuses and two network isolators in these rooms. Also, I don't know if I might want to install residual current devices (RCDs) at some point. Currently, they are still very expensive, but if they are available for 30 € in a few years, then I would also need two RCDs for each room. The fuse box will then eventually be as big as my entire pantry.

Therefore, my goal was actually to combine light and power per room with a 1.5 supply line (13A). Then I only have 3 instead of 6 network isolators at the end and maybe only 10 residual current devices instead of 20. And of course the space I would save.

You are thinking about residual current devices but only want to install 1.5 mm2?! Well, I am a trained electrician and a graduate electrical engineer. Even though I am not working in the construction industry, I am quite well informed on the subject since I am currently building myself. However, I had the installation planning done by a professional planner. I will install one circuit each for lighting (1.5 mm2) and sockets (2.5 mm2) for every large room, but I combine smaller rooms (hallway, guest WC, ...). Regarding the load, for example living/dining room: hi-fi, TV, uplighter (300 W), maybe raclette or electric grill and you are already well above 2500 W.

You are thinking about fire protection switches, but only want to install 1.5 mm²?!

Does one exclude the other? Is the risk of a house fire with 1.5 mm² and 13A higher than with a 2.5 mm² cable and 16A?

I will lay one line each for lighting (1.5 mm²) and sockets (2.5 mm²) in each large room, but I combine smaller rooms (hallway, guest WC, ...).

So you connect sockets to the next larger room and lighting as well?

On the topic of load, for example living/dining room: Hi-Fi, TV, floor lamp (300 W), maybe raclette or electric grill, and you are already well over 2500 W.

The large living/dining/kitchen area would be protected by two circuits for the standard connections (stove and major appliances separately).

I understand what you mean, but apart from "it may happen that your fuse trips" and "then you sit in the dark," I am missing a real reason. That is acceptable to me and happened about 5 times in my houses and apartments in the last 30 years. If it were to say the cable gets too hot and burns through the wood fiber insulation, that would be something else, but as a layman I see little reason for concern because I only use a 13A fuse.