ᐅ Preparing Electrical Wiring for a Smart Home in New Construction

Hello everyone,

We are currently planning our new build, and we will be installing the electrical system ourselves (an electrician in the family).

I want to consider the topic of smart home technology early on, even though it won’t be installed right from the start. I would appreciate tips from those who have already done something similar.

So far, the plan is to use push-button switches (for example, for lights, blinds, etc.) and run separate wiring through relays in the distribution board to control the 230V (230V) lines.

Additionally, I want to install window contacts and sensors (temperature, humidity, and motion) in all rooms and be able to monitor these later via the 24V (24V) lines.

I’m interested in what else I should include early on to be well prepared for smart home integration later. I’d like to avoid radio/wireless connections and pure bus systems if possible.

As an IT specialist, I am considering using a Raspberry Pi, but it seems to me that even with expansion boards, it has too few ports.

I look forward to your tips and suggestions. Links for further reading on the topic are also welcome.

Best regards from Westerkappeln,
Jens

jeti79 schrieb:
I would like to avoid wireless connections and pure bus systems whenever possible.

These two usually exclude each other....

jeti79 schrieb:
As a computer scientist, I am tempted to use a Raspberry Pi, but even with expansion boards, it seems to have too few connections.

Possible use as a web server... rather unsuitable as a central unit for home automation... or it involves a lot of tinkering...

Which system besides Raspberry is being considered? “Smart home” is not a protected term like “turnkey” and can mean anything from a simple power strip with remote control to a house that thinks for itself and handles many tasks before you even realize it.

To start, read this:

https://www.hausbau-forum.de/threads/smarthome.12732/

Hello Jeti79,

As a software developer, I faced the same problem this year: how to set up the wiring to install or enable home automation.

My solution was a star topology wiring from the devices (sockets, roller shutter motors) and sensors (push buttons, 6-button switches from G**a, glass break and opening sensors) to the distribution cabinet.
Well, the distribution cabinet is quite a project.

I used Homematic Wired for the home automation system. The central control software runs on a BananaPi, which is much faster than the original target hardware – installation went smoothly.

I implemented some light switches and dimmers with Eltako devices because I didn’t want to risk a total failure if something went wrong with the home automation. So far, everything works perfectly.

It’s really important to be clear in advance about what you want to achieve and how!
Think a lot, read, exchange ideas, and then it will work out. Maybe also find an electrician with experience.

Regarding “KNX”: back then it seemed too expensive, but now, seeing how much money I have spent, I probably could have gone with KNX. :-(

Best regards,
bjjfan

Thank you for your answers!

Mycraft schrieb:
That excludes each other....

I don’t quite see it that way: an acquaintance wired it exactly like that and implemented it with a Siemens PLC control. Since I have no experience with PLC programming, this solution is less suitable for me.

Mycraft schrieb:
Which system besides Raspberry is preferred?

So far, I don’t have a preferred "commercial" system. I have researched Loxone and Homematic, which come closest to my desired solution. However, I am currently reluctant to use an expensive, closed system. The Raspberry gives me a very "open" impression.
(For context: I am still relatively early in my considerations)

torsan schrieb:
My solution was a star-shaped wiring from the consumers (outlets, roller shutter motors) and sensors (push buttons, 6-button switches from G**a, glass break and opening sensors) to the distribution cabinet.

I’m also aiming for star topology wiring to stay flexible in system choice (meaning: all cables first run from the switch/button/sensor via 24V to the control panel, and then 230V back to the device/load).

torsan schrieb:
For home automation, I used Homematic Wired

Did you have to use Homematic products for the implementation? These seem quite expensive for a “wired solution.” (A Busch-Jaeger switch costs about 6€; so far, I haven’t found a Homematic switch without wireless capability.)

torsan schrieb:
It’s really important that you are clear in advance about what you want to achieve and how!

I’m currently working on that:

I imagine operating everything quite conventionally with push buttons at first (lighting, blinds, etc.) and gradually switching to an automation solution later. That’s why I’m considering pulling patch cables/insulated doorbell wire to the push buttons and switching them via 24V control relays to operate power relays for the 230V supply, allowing a future conversion to automation to be smooth and largely wireless-free.

Am I too far off from what might be feasible?

jeti79 schrieb:

But since I have no experience with PLC programming, this solution is less suitable for me.

I would stay away from a PLC. I always keep in mind that I might want to sell the house someday or make changes a few years down the line.

jeti79 schrieb:

I looked into Loxone and Homematic, which are closest to what I want. However, I’m still hesitant to use an expensive, closed system. The Raspberry Pi seems very “open” to me.

I also debated between Loxone and HM. Raspberry was not an option for me. It’s not very well made and doesn’t feel very reliable.
You should really take a look at KNX. In the long run, the costs probably aren’t that different, and it’s THE standard for home automation.

jeti79 schrieb:

I’m aiming for star wiring to stay flexible with the choice of system (meaning: all cables initially run from the switch/sensor/controller with 24V into the control cabinet, then 230V back to the device/consumer).

Good call.
Also, run KNX bus cable to every switch. I forgot to do that and regret it now. :-/ Now that everything works, I would like to have the light switches connected directly via 24V as well.

jeti79 schrieb:

Did you have to use Homematic products for implementation? They seem rather expensive for a wired solution. (A Busch-Jaeger switch costs about €6, I haven’t found a Homematic wired switch without radio)

No, I didn’t have to. But I had the choice between Loxone, HM, and KNX. HM seemed the most sensible for my application.

For manual control of roller shutters, lights, and sockets, I installed a PLC switch from G**A. So, in every room, there’s a conventional switch for the ceiling spots and above it, a 6-button switch for the “bells and whistles.”

jeti79 schrieb:

I imagine doing everything conventionally with switches first (lights, shutters, etc.) and later gradually switching to automation. That’s why I am considering running patch cables/insulated bell wire to the switches and using 24V control relays to activate contactors for the 230V supply, allowing a later upgrade mostly without wireless.

Am I far from a realistic approach here?

Nope. That can definitely work.

Just keep in mind that your intermediate solution will require effort too. Larger electrical cabinet, hardware layout, wiring. It can get complicated quickly and in the end, you might not feel like making any changes because you lose track of everything.

Cheers, torsan

torsan schrieb:
Good decision.
I would also install KNX bus cables at every switch. I missed that and now regret it. :-/ Now that everything works, I would have liked to connect the light switches directly with 24V as well.

I'm stuck here: So in addition to closing the 24V circuit, I would need extra conductors to potentially use KNX? How many should be planned "per switch point"?

torsan schrieb:
Just keep in mind that your interim solution also involves effort. A larger electrical cabinet, hardware arrangement, wiring. It quickly becomes confusing and in the end, you might not even feel like making any changes because you’ve lost track.

That’s to be expected – but worse for me would be if I wanted to implement it, but the opportunity was gone just because I saved 500€ on extra cables during the new build...

Best regards,
Jens