ᐅ Electrical installation – Facing a decision dilemma

Hello,

First of all, thank you for such forums that allow people to exchange ideas. I hope to ask many questions here and receive meaningful answers. Since I’m new, I also hope this is the right category.

I bought an older house that needs quite a bit of work. Each floor has about 80 sqm (860 sq ft), consisting of a basement, ground floor, first floor, and a converted attic, which totals about 320 sqm (3,440 sq ft) of floor space.

Now, I want—actually, I have to—completely redo the electrical system because it is outdated.

I have an electrical panel that I had planned to install in the basement and run everything from there.

For the past few days, I have been considering whether to install a large main distribution board in the basement and then sub-distribution boards on each floor.

I have listed some advantages I see in advance.

Advantages:
1. Long cable runs could be avoided, since I would only need to install the main riser cable from the basement to each floor.
2. In case of a problem, it would be easier to isolate the fault to a specific floor.
etc.

Disadvantages:
1. It would require more residual current devices (RCDs).
2. Instead of one main electrical panel, I would have a large distribution board with the meter plus three sub-distribution boards for each floor.
etc.

I would appreciate it if you could share your thoughts on whether this makes sense or not. I have to decide myself anyway, but it helps to read other opinions.

Regards,
Markus

Both approaches actually lead to the same result. So whichever way you do it, it will be correct. In the end, it’s just a matter of personal preference.

By the way, you can also strictly separate everything by floor level in a large cabinet to make troubleshooting easier later on, but as an electrical installer, you probably already know that. Who am I even telling?

Long cable runs are naturally not ideal. This inevitably leads to using 2.5mm² (approx. 13 AWG) cables for distant sockets, etc., which means higher investment. On the other hand, you don’t need a riser cable in that case.

Also, a large distribution board will likely require a bigger investment than three smaller ones.

However, with a large distribution board, you can control and monitor everything from one point. Both methods have advantages and disadvantages that more or less balance out.

I found a large one in the utility room more practical. Everything is in one place, and if something trips, you don’t have to search for long—you can see immediately what’s going on.

I had an electrical distribution board installed on the upper floor. For me, the main advantage was not having to go down to the basement if a fuse blows on the upper floor. In terms of cost, I believe it is about the same and doesn’t make much of a difference.

RCDs don’t cost a fortune. I will probably install a main one in the basement for the basement/ground floor and a sub-distribution board for the upper floor.

Hello,

thank you all for the comments.

MyCraft, thank you for the detailed input; I also find your arguments very good.

Joedreck, I had the exact same thought about the long distances.

MIA_SAN_MIA_, you are right about the RCDs, these days it is not as bad as it used to be.

Since I am very tech-savvy, new ideas and thoughts keep coming to me that I could implement. Based on what I asked and your comments, I now feel more comfortable with the idea of installing a distribution board on each floor. I will gather these new ideas and see how I can combine them.

Best regards
Markus

Here’s a differing opinion: I would base it on how many circuits are planned per floor.

In a typical single-family home with only one living unit, I don’t think it makes sense to install a sub-distribution board for each floor. You would need significantly more than 6 to 7 circuits per floor before a sub-distribution board becomes practical. From a cost perspective, even with longer cable runs, there is no real difference. The extra costs come from the panel itself, the riser cable, the residual current device (RCD), and possibly wiring materials. Additionally, you need to find a suitable space on each floor to install the panel, which isn’t necessarily attractive. And honestly, how often does a fuse trip in a new electrical installation with new household appliances? Maybe once a year? And usually, you can tell immediately which device caused it, because it happens when you turn it on or plug it in.

However, if you install a large number of circuits, then it might make sense. Even then, I would combine two floors per panel (basement + ground floor / upper floor + attic).