ᐅ Renovating the Electrical System in a 1961 Townhouse: How to Plan the Wiring?

Hello,

we have purchased a terraced house built in 1961. We had assumed that we would need to replace the electrical distribution board to retrofit residual current devices (RCDs). However, the electrical system was reportedly renewed in 2009. Upon closer inspection, it turns out this does not apply to everything. Some wiring from the original construction is still present, and the upper floor and attic are connected to only one circuit breaker.
Since we need to work on this anyway, we are considering renewing the entire electrical system to bring it up to a proper standard. We have kept the kitchen and bathroom as they were and do not want to open walls there. We expect that our entire planned renovation budget will now probably be consumed by the electrical work.

Currently, I am thinking about the best way to route the cables (floor plans attached). I have had two electricians on site so far. When I asked both about wall thicknesses, groove depths, and chasing around the chimneys, both said it would not be a problem as no house has ever collapsed because of that. They were also not willing to use conduit. I already have a quote from the first electrician, which I consider too expensive for a basic setup.
The second electrician appealed to me much more overall (except for the chasing issue), and he would also agree if I did the chasing and wiring myself, and he then handles the distribution board, equipotential bonding, and final inspection. That would suit my budget better and also give me the flexibility to add more sockets without constantly worrying about costs. Moreover, I believe I would take more time to do a careful and correct job than a company that wants to finish quickly to move on to the next site.

I want a modern electrical system with many sockets, circuits, and network outlets. My main question is how the electrical wiring can best be installed. Most interior partition walls are only 11.5 cm (4.5 inches) thick and probably must not be chased horizontally, and the 24 cm (9.5 inches) thick exterior walls may only be chased up to 25 mm (1 inch), leaving barely enough space for a 25 mm (1 inch) conduit. The two chimneys are still in use (a gas condensing boiler and a wood-burning stove), and I wonder how to run cables past them.
The bay window in the living room includes a radiator niche, windows, and roller shutter boxes, so I do not see a good way to route cables and conduits there.

I had considered running the wiring below the ceiling and installing a boxing with indirect lighting around the perimeter, but I think that would be a lot of work if done throughout the house.
We are actually under some time pressure; on the other hand, I do not want to cut corners on the electrical system now and hope not to have to touch it again for the next 30 to 40 years.

How would you proceed here?

Of course, I could invite three more electricians, but at the moment, I don’t feel they would pay much attention to the requirements, and that would also take a lot of time.

You might believe that. However, the electrician does this every day and has so much experience that they will complete the work much more neatly under stress than you would, even if you take your time. Who creates the plan for where the cables need to go? What training do you have? Any vocational training?

You are under time pressure... keep in mind that you need to plan at least three times the amount of time for the work compared to if the electrician does it, plus additional time to get materials and borrow tools...

It won’t be worth it.

I completely agree with @xMisterDx (which doesn’t happen often). If you don’t have prior experience through your profession or about 10 private building projects, it’s better to leave it alone. You can still ask if the electrician will let you assist as a helper, which might save you around 500 EUR on the total bill (if they’re kind, because usually an untrained person takes more time than they save), but next time you’ll know better what to watch out for.

That you feel the need to emphasize that so much... well, suit yourself.

The 500 euros can come back to haunt you. If something doesn’t fit in the end, for example an insulation resistance test, the clever electrician has a hundred ways to blame the layperson or at least put part of the blame on them.

“YOU pulled the cables off the reel and cut them to length. You probably pulled them over an edge and nicked the insulation.”
“YOU hammered in the cable clips; you must have hit a cable.”
“YOU did…”

You might be able to handle the low-voltage part yourself. Nothing particularly serious usually happens there. Unless you are professionally skilled and confident in doing everything... The installation zone is 30cm (12 inches) below the ceiling. That’s where you can chase and lay cables. Normally, I always recommend conduit installation, but in a renovation... Empty conduits can be easily installed in concrete ceilings. However, in your case, the effort is significantly greater.

What is meant by "low voltage" in this case? Extra-low voltage? Low voltage?