Which technique to use in the fuse box as central light controller?

I already have some z-wave wallsocket-switches implemented with openHAB 1.83 which work fine with devices connected via wall sockets. But I would like to control the hardwired lights in my kitchen/diningroom/livingroom/staircase too. I could use z-wave modules behind the switches, but would prefer a central and hardwired solution as I have an additional fuse box (or better cutout box) in my house just for the lights in these rooms, where I can reach all the cables to the different lights directly.

Is there an afordable alternative to implement some central controller in the cutout box for at least 8 lightcircuits (preferable connected via powerlan, as I do not have a LAN-cable in that box)?

Hello Jörg

If you like to use your wallswitches as well as remote controlled switching capabilities, I recommend to use flush-mounted zWave devices.
They are small, reliable and silent.

You can even use them central in your fuse box. But be aware, how to use the wall switches.


Thanks for your reply, but as I have to control more than one or two lights, I would prefer one bigger device instead of a lot of smaller ones. Meanwhile I took a look at Homematic switches which look good at first sight. But then I found out that they have no entry for existing pushbuttons. That is very important for me, as I use Eltako-Relays for some of the lights, and want to keep the existing pushbuttons for manual switching.There are ways to extend the Homematic switches the way I need them, but I would prefer a “out-of-the-box”-solution.

Any ideas?

fibaro or aeon relay or dimmer modules

Hello Jörg

As far as I know, only KNX provides multible (more than 2) switches. The price per connection is much more expensive than an port of a zwave device.

Also you build a single-point-of-failure. If you have only one device for all lights, and this device fails all lights stay off. When you use single or double switches only one or two lights fail.[quote=“jlemmer, post:1, topic:19969”]
s there an afordable alternative to implement some central controller in the cutout box for at least 8 lightcircuits

You talk about 8 lightcircuits and no dimming, so you can use 4 fibaro double relay switches (about 50€ per piece = 200€) which sounds afordable to me.
This 4 pieces can be mounted in your central box :slight_smile:

Another question:
Do you really wire the switches in every room to the central box as well as every light?
This sounds very overdone to me.
Normally you use this type of wireing when you build a cabled bus system like KNX.


Yes, I really had all the wires brought to that one box, when I built the annex 13 years ago. Everything there is quite compact, so it was not to much additional effort. That means, that I can do some hardwired sort of automation there. 13 years ago I did not think of the things possible now, but wanted to be flexible to rout between switches and lights.

So I have a lot of pushbuttons in this area that can be connected to the lights in the ceiling and a lot of walloutlets I installed as reserve for future use. That is nothing I use every month, but it was quite helpfull over the past years in different situations. So I could connect a walloutlet directly to power when I installed a wallclock, that needs permanent power, added an other walloutlet to one of the existing circuits, …

Now I would like to keep the pushbuttons (235V) and just replace the relays to a more intelligent Version that can be used in the old fashioned way (woman-acceptance-factor) by still pressing the pushbuttons, but that also “knows” its own Status, report it to openHAB and allows a concrete switching to on/off (not just the toggling, as an additional pushbutton).


I know the WAF very good :slight_smile:

Go with zWave devices and your wife and you get happy.
My wife also wanted everywhere switches. Nowadays she complains that she have to clean these useless things :stuck_out_tongue:

Perhaps a bit industrial, but I use these impulse relays

which allow for multiple pushbutton controls
cheap chinese relays
to monitor the light status for feedback
Interfaced to Openhab with Modbus
whose spare inputs can be connected to cheap burglar alarm PIRs

Terribly old fashioned; clonky relays, all hardwired, works, still works manually without openhab.

Sounds really interesting, but as I have no experience with RS 485 and Modbus this is a little bit “overwhelming” for me. Do you have a wiring scheme for that?

The next problem is, that I do not have RS 485 wiring in that fuse box, and that my openHAB host is a Raspi that is located in my living room and should not have to much cables attached. So I think I would need something to gateway from RS 485 to LAN/WLAN. I thought about a second Raspi with a RS 485 shield (and WLAN), openhab and MQTT.

I want to try a master/slave Installation of openHAB for an other reason, as my home is very large, and I want to controll things in attic, while the floor in between is rented out, so I will have to learn about that anyway (but I heared that this is not so easy too).

Modbus can be essentially a single twisted pair linking everything. Up to a km long.
In practice you probably have DC power supply to think about as well with wiring.

Cheap gateways from ETH LAN to RS485 are available,

this particular one supports Modbus directly i.e. the remote host talks Modbus-TCP over the LAN and the gizmo talks Modbus-RTU over twisted pair to slaves.
Not all do that, some only provide ‘remote COM port’ and I’m not sure how/if that works in a non-Windows server.

There are similar WiFi-to-RS485 gizmos.

So you could run a ‘remote floor’ from a single Cat5 cable, running either Modbus or LAN (probably the more flexible choice). Or WiFi. No remote server needed (for this purpose).

An alternative hardwired system approach could use Ethernet relay modules - though these seem to be costly, and I haven’t found many with digital inputs (for sensor contacts) that you’d usually also want for an OpenHab project.