How to prepare for setting up a smart home or how to approach the topic?

Hello everyone,

this summer we will do a complete renovation of our house. I am thinking about smart home systems for this. I have seen wireless standards like Zigbee, Z-Wave. Or also a Hornbach gateway which apparently can connect different standards.

In principle, I am a fan of wired systems. There are also systems like KNX, Homematic, etc. With these systems, I would like to remain as flexible as possible. Besides roller shutter, lighting, and heating control, I could imagine doing individual customizations like: "notification when the carbon monoxide detector issues a warning," water leak, humidity, or a sensor that detects movement and triggers something or starts a script (SMS, email, or push notification, depending on what is easier to implement or possible).

I thought about whether it makes sense to start with an open-source tool like iobroker or FHEM, get familiar with it, and then integrate the first actuator, sensor, or switch? This would already raise the first questions about how the whole wired system looks (hardware & cables). Especially if one later realizes that they want to use a different system. Aren’t most cable systems (with regard to the cable) largely the same, especially if more than the necessary number of cores are laid? For example: network cable with 4 x 2 x 0.25mm².

Best regards

A very good day :)

Planning for whatever it may be is always a very good idea that I always recommend to my clients.

For wired systems it is quite simple. For every connection point, at every location where you can imagine "I could use something here," pull in a bus line. Very important: BUS line, not network cable; the difference lies in the shielding. For wired systems (KNX) you only need 2 wires, red and black + and -. Once the cables are in place locally, the rest is easy to retrofit. Normal NYM cables can also be laid alongside bus cables (but please in different conduits), afterward you are definitely prepared for any eventuality.

VERY IMPORTANT: Label cables properly, get an electrician involved before the walls are closed, who inspects the cables and checks that nothing has been forgotten.

It is more effort, but for at least 20 years you are prepared, opinions, financial resources, and needs can always change.

If you have further questions, feel free to contact me, I will be happy to answer them.

Best regards Ricco Neugebauer

Thank you, that is very kind. I will provide a bus cable. However, when I look at such a bus cable (e.g., green KNX EIB Y-(ST)-Y 2x2x0.8), it looks less shielded in the photos than a CAT7 cable.

1: Question: Is the outermost PVC sheath thicker, or what else distinguishes these cables? With CAT7, the individual conductor pairs are additionally shielded.

All the bus cables could probably be routed star-shaped to the main distribution box or technical room, even if initially more cable would have to be laid (and the advantage of some bus systems (ring line) would not really be exploited). The box should certainly be dimensioned a bit larger than usual. (Unless the smart home gets its own cabinet). For a 2- or 3-family house, the architecture would have to be well considered anyway, since each apartment should have its own sub-distribution/fuse box inside the apartment.

2 Todo: Next step for me: To create a floor plan with the desired components and control requirements. This will probably result in further questions or tips from you.

What I also need to understand regarding architecture or topology is the following: In conventional electrical wiring, each room usually has its own fuse. In the KNX example installations, I see that each actuator is assigned a fuse.

3: Question: Should multiple actuators not have several fuses? For example, kitchen sockets. Or a multiple actuator for all ceiling lights in an apartment.

4. Question: Do heating controllers have only a bus cable or also NYM? (They usually don't need much voltage). The same applies to roller shutter motors.

Furthermore, I have found the following advantages of a PM compared to standard motion detectors (which only can switch ON/OFF) in another thread:

a. Dimming lights up/down
b. Detecting and transmitting temperatures
c. Detecting and transmitting brightness values
d. Controlling multiple light sources
e. Controlling other PMs
f. Transmitting presence information to heating/ventilation/cooling/shading/alarm systems and thus controlling them
g. Constant light control (always maintaining the set light value in the rooms at any time)

5. Question: I can understand b and c as advantages. I still find d, e, and f difficult. The control should be done by some central device where the entire behavior should be programmed when a certain event occurs.