Bus systems - wiring, planning, etc.?

PowerLine modulates a frequency onto power cables (massive copper conductors). The whole house is under "radio frequency exposure" constantly! PowerLine is and remains a makeshift solution, not only in IT but also otherwise.

already said very correctly: This and other makeshift solutions have no place in new buildings! Absolutely not!

Any disturbance in the power grid (cheap device or defective device) leads to disturbances in the PowerLine network. Not to mention safety aspects.

You may notice: I practically "hate" PowerLine. There is nothing more unreliable (possibly except poorly implemented WLAN).

Also, as already mentioned, it serves to supplement the LAN (wired) infrastructure, never as a replacement. Even if this is sometimes propagated as such by larger companies.

No, it practically costs nothing in new construction. Because it is pulled in directly with the NYM cable. It's maybe 100-200 euros more per typical single-family house.

It depends on who implements this for the new building. If standard electrical work with the general contractor has been agreed upon, something like this often doesn't work because planning is not done and there is insufficient time to carry out the planning. btw: "saving" switch batteries is not smart but simply minimizes the physical number of switches/buttons.

It depends on who is implementing this for the new build. If standard electrical work with the general contractor has been agreed upon, something like this often doesn’t work because planning is not done and there is insufficient time to implement the planning.

The passage referred to the fact that laying bus cables practically costs nothing if that option has been chosen because the NYM cables have to be laid anyway.

btw: "saving" on switch batteries is not smart but simply reduces the physical number of switches/buttons.

Switch battery = usually "not smart" since a control point is created for each function and every device. Because you have to be able to operate it somehow. That is a way of thinking from the past.

In contrast, a room controller as provided by KNX is already a huge difference and not a simple savings in physical switching points.

On the contrary, often you can even accommodate many more buttons in the same room. And they remain very easy to operate. The standard switches in the 55mm grid are IMHO far too large anyway for simple tasks.

By Powerline I simply meant the use of the power cables (regardless of what for). And kind of yes and no, Wi-Fi does replace LAN. Personally, I try to avoid LAN as much as possible. Spontaneously, I would actually set up a central point for the modem, then supply only APs via LAN from there and all devices via Wi-Fi. I'm talking IT now, not Home Automation. That means PCs, notebooks, tablets, phones, FireTV etc. etc. All via WLAN (=Wi-Fi). Okay, the NAS would also be located next to the modem and are LAN. But otherwise... But okay, then technically it obviously wasn’t possible to use the power network cleanly. Because a star topology is the "cleanest" in terms of speed and peer-to-peer communication, but the most complex in hardware implementation. I don’t mean that every meter of cable is that expensive. But let’s say, for example, you want to retrofit the attic. Then you have to run cables through the entire building so that you can supply the attic. With a power network, that wouldn’t have been necessary. Nor with radio. Okay, so you should best plan a lot of cable routes very very early and know exactly where each device should go. And where each piece of furniture should be. And then, just to be safe, a conduit in every room? The planning really becomes quite complex

By Powerline I simply meant the use of the power cables (no matter what for).
And yes and no, Wi-Fi does replace LAN. Personally, I try to avoid LAN as much as possible.
Off the top of my head, I would actually set up a central point for the modem, then supply only the APs via LAN from there and all clients via Wi-Fi. I'm talking about IT here, not home automation. Meaning PCs, notebooks, tablets, phones, FireTV etc. etc. All via WLAN (=Wi-Fi).
Okay, the NAS would additionally be located next to the modem and connected via LAN. But otherwise...
...

Yes, you are right that the effort to lay bus cables (CAT7 ...) once (somewhat) is higher.
BUT (the amount of LAN cable) almost never happens later on. At least not at the costs, i.e. effort, as in the rough construction phase.

Well, and what comes out of it I see in many single-family houses built in the last 15 years when they want to subsequently place a NAS here, a TV there (as a streaming client via LAN), or even just an additional WLAN access point.

There are only 2-7 pieces (simplex) of LAN cables planned and installed for an entire house.

The house stands ... 50? 100? years? No idea? At least too long for such mistakes.

The NET transfer rate of LAN is factually multiple times higher than with WLAN!
(even if you plan expensive WLAN APs every 3 meters) which in turn is then more expensive than LAN which you then need anyway to control the access points.

Sorry, from more than 30 years of IT experience I can tell you: Lay as many LAN cables as you can, also plan plenty of WLAN. Something will be missing later anyway.

The cost savings (pipe dreams) of some responsible persons who plan and implement a building network (IT) exclusively via WLAN will later be undone by elaborate re-cabling.

And whoever planned an unfinished attic in a new build should certainly lay LAN cables etc. there alongside pipes for heating, wastewater – right?

I have to disagree with you on that. Wifi cannot replace LAN. A user here in the forum once summarized it well. Even if you consider yourself tech-savvy, you probably are not deeply familiar with the topic here. With Wifi on the 5GHz band, even with the best reception and only one user (client), you do not get anywhere near the speed of a proper LAN. We are not even talking about 10Gbit, etc.... Usually, for example, in the living room you have a cluster of clients. They all have to share the connection. Many APs are also problematic for the average user. You have to manage the frequencies and transmission power carefully... In a new build, LAN wiring hardly matters. Retrofitting later is laborious. These are exactly the cases where residents use crutch solutions (repeaters, powerline LAN...) with up to halving the bandwidth. If an electrician tells you that you only need Wifi, please politely ask him to leave immediately....