Help: Build of new home

Hi guys,

sorry … my first post here and I hope that I have posted in the right place :slight_smile: Forgive me if not.

I am at the beginning of a new build of a new house here in Australia. I have renovated another house before and centralised all the Ethernet in a switching cabinet which worked absolutely fantastic. I will repeat that.

I want to take a step further and integrate home automation and OpenHAB. There are a lot of topics about hardware and some on wiring but I have not really found a good article helping me with all my questions.

Here in Australia we have a switchboard standard AS3000:2007 which does not state that you cannot have 230VAC and 24VDC in the same switching cabinet. So this would allow me to centralise all my lights and switches into a switching cabinet and switch the lights with a 24VDC / 230VAC relay. So cabling for lights is std 240 VAC electrical cable.

If I go with 24VDC to my switches I could just simply run Cat 6 Ethernet cable to all my switches. So later if I go for full blown wifi or smart switches (e.g. Mr SUPERHOUSE).

I am looking at Phillips Hue lights atm … but as other article mention that gets expensive quickly and if bridge goes down the light doesn’t work.

So could you please help me with the following:

  1. Is Cat6 to switches, 240VAC to lights, relays a recommendable approach?
  2. A lot of people seem to be concerned that they can’t switch lights on if WIFI breaks down … This really mostly happens when power out … then the lights don’t work anyway … thoughts?
  3. Any guides on sizing the switching cabinet? At this stage I would cater for relays, safety switches / circuit breakers, 24VDC PSU.
  4. If you centralise lighting to switch board how do you handle dimmers? Any good suggestions?
  5. I plan to use Synology NAS as OpenHAB platform. Better to use Rasberry PI?

I have so many more questions but that’s a good start. Thanks a lot for your help.


I am tagging @chris since he recently moved to New Zealand, almost next door. He develops the OH Z-Wave & Zigbee bindings

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we finished building our home in germany just a month ago and i chose knx.
if you do it yourself you can save a lot of money and it is wired.
basically similar to your approach with the ethernet cables.

there’s a binding for OH as well (i tried it in my test setup and it worked).

i am pretty happy with the solution - i automated a lot: lights, shades, air flow, heating (although i got rid of the actuators beacuse my heat pump works way more efficiently without it).

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Ok, I have to look into this (originally from Germany too :slight_smile: ). I will use somfy blinds which I looked up how to integrate them already. Which blinds did you use?
I am experimenting with the ESP8266 a bit at the moment but I will look closer at the KNX and see if I get a test setup working.
Thanks a lot.

Thanks. I have a lot to learn.

i would never have guessed your home country by looking at your username :wink:
i just use standard blinds that are controlled via a knx controller (like my lights (dimming, switch and led color).
If you build a new house keep it simple (knx for example).

you can add as many OH stuff as you want but the “base” should be an established system (knx/loxone …)

i played with some esp too but trust me - you got a lot of work to do.
i used the esp to push humidity c02 and pressure to a mqtt server and then to OH but now this is done by an integrated sensor of a knx presence detector.

you should definitely read something about knx / loxone and not rely on “self built” stuff in the first place if you have all options

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Depending on the budget and sparky I would just let them install everything and then change it later. Make sure you tell the sparky you want a nutural at every light switch.

If you got money to burn C-Bus - Bindings | openHAB

If you want to do it yourself and pay less then 8266 are the way to go.

I use some tasmota stuff to make implantation a 5 min job.

If you want the kettle boiled when you get there

For my fans and lights I use SONOFF IFan03+RM433 flashed with tasmota like $15 each with remote. I just bought a blank wall plate from bunnings and double sided taped the remote to it.

So I automate 4 rooms with fan OFF/SLOW/MED/FAST and light ON/OFF with google assistant for under $100 thanks to openHAB community


I started with hue. Yes they are great bulbs but…
Starting again I would go Zwave bulbs.
If you want to retain local hardwired buttons too hue is not the way. I use fibaro modules with the hues but it’s a fair few rules for this to be in sync correctly.

Plus the cost defo… my kitchen cost £1000 for the hue gear - Downlights also need to be deep enough as the hue bulbs are much longer

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Thanks mate,
I am not sure if I want to go to the extend to automate all lights but the least at this stage I can do then is to switch them all via relays. Quite a common thing in Germany since years. My dads house has this and was build like 30 years ago … good old Busch & Jaeger gear :slight_smile:
Lots of research and planning to do I guess.
Would you have a recommendation or parts list for the Zwave stuff? That would allow me to build a little test setup to get my head around?


For Z-Wave the devices vary somewhat by region due to frequency differences. For instance, UK devices would not work ( or be legal) in Australia.

For instance, my preferred brand os for use in North America only.

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If I would have a chance to start from zero I would wire all I plan to automate to a PLC.

Protocols change, PLC will be there for a while

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Any z-wave relay module you can get for the switch (can put above light for neutral), then use the 2 cables to the switch onto the relay module but don’t wire the light in. Light fitting now permanent live onto it instead of switched live. Set association from the module to the bulb to switch on/off. Can’t remember if for instance fibaro dimmer can also send dimming by association or not and bulb receive…

Then color etc from openhab.

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Yeah, thanks. Thats why I started this conversation here. I just want to get the basics right e.g. centralised wiring. At a bare minimum I could just let the electrician put relays in for all the lights and make it smart later when I have time. I will spend some time now to research knx and zwave and then see what makes sense. I dont want to do too much as I know people who hate that their house had too much automation.

That’s just how I’d do in an existing retro fit. Plenty of other ways :+1:

Hi Andreas,
I have built a house in New Zealand, ( basically same elect regos) I have wired all my lights to boards with relays on. What to use to control? I have looked at KNX, and Cbus and they’re really expensive in NZ. I have about 140 lights ('cos I want to control each one - not a room-full) and about 140 switches needed. That’s a lot of money, so I am developing a wall switch that will fit in a standard NZ wall plate box. It will communicate using modbus. One can buy modbus relay boards at realistic prices, so that will be my first revision. Later I will create modbus driver boxes with full dimming and direct LED drive outputs. This means I am able to use common everyday downlights which are cost effective.
Almost all the KNX stuff uses 68 square boxes, standard in Europe.but oddball here. This means I’m wiring my switches ( and relays) onto one long serial cable, and I’m using cat5/6 cable. One pair for the serial, and the other three pair for line power to the network connected switches. If you have any interest I can make more switches. As the NZ wall plate is very nearly the USA wall plate size there could be USA people who would like some too.The only rider to all of this is time. You no doubt know building your own house takes a lot of time, but I’m getting there now. Good luck with your venture.

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Thanks David. I have a friend working for Schneider / Clipsal and she said that KNX is not supported by them in AUS, only CBUS. So I have to look at the KNX AUS webpage and ask them what suppliers are here in Queensland. Hence I was looking to make my own wifi switches with the esp8266. But I have to smarten up a bit before hand. A long time ago that I have designed an electronic circuit.
House built is in drawing phase … well just about to. So I have a bit of time on my hand. So a little esp8266 circuit in the switch could do the trick. You use poe supply so you can just plug them into a poe switch. This would even allow you on controlled switched to turn them on and off remotely and not 24 dc psu required. But i need to make a prototype.
I agree that the knx and cbus solution cost you an arm and a leg…
Thanks again for your time and input.

@dangerous_dave our developer for Z-Wave & Zigbee, @chris just recently moved back to NZ from the UK. I think his preference is to use Zigbee but I will let him state his preferences.

I’m in NZ, as stated pretty much the same electrical codes as Aussie.

What I’ve personally done which works exceptionally well…

  • For lights, run Fibaro ZWAVE modules for all lights (saves on mucking around with cabling) and run OpenHAB on a Raspberry Pi with Aotec WAVE USB stick as the ZWave controller. Don’t use a NAS!

  • For blinds, run 12VDC cabling to the top of all windows for blinds. Just make sure the correct gauge wire is used for the distance. I run all these cables back to a cupboard in my office. I then wire them into a CCTV power supply box mounted to the wall, and fed by UPS (incase I need to open blinds when there’s a power cut)

  • I run 12V blind motors from Aliexpress
  • I also run a Sonoff RF Bridge with Tasmota/Portisch firmware and use this to control all blinds UP/STOP/DOWN in turn via MQTT in OpenHAB

As I was retrofitting my existing roller blinds, which had larger tube sizes than the blind motors, I had to design and 3D print roller blind adapters to suit. But if you buy the right size tubes for the blind motors obviously you won’t need to do this.

Also consider prewiring CAT6 for security cameras. Whilst many are wifi these days, I personally prefer cabled as typically more secure than wireless. Run POE cameras too, so you can power them from a POE switch rather than extra 12V cabling.

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I’ve done a very similar thing to my apartment, so can share some experience.

  • Is Cat6 to switches, 240VAC to lights, relays a recommendable approach?

I would say “yes”. Yes, you can’t revert to oldstyle plain electric installation any more, but… Who cares about the past; it’s 21st century! I did so.

  • A lot of people seem to be concerned that they can’t switch lights on if WIFI breaks down … This really mostly happens when power out … then the lights don’t work anyway … thoughts?

Well, in my apt i even reserved some wiring for a UPS, which could power the automation and maybe some lights i would consider emergency. Not using it still; power outages are extremely rare in my location. You may have a different situation though. In this case your solution, i suppose, would depend on how bad the reality is plus how deep your pocket is. Anything from a medium sized UPS up to a full-blown emergency gasoline/diesel generator.

Just try to avoid dependency on any clouds, a good system (IMHO) is a self-sufficient one. Yes, unfortunately such solutions may not always be available.

One more good bit of redundancy is to have some basic local controls. My modbus relays have external inputs, to which pushbuttons can be hooked; so even if the whole automation system is down, i can switch on and off my lights, and control all the equipment in a traditional way. You can try to find something like that.

  • Any guides on sizing the switching cabinet? At this stage I would cater for relays, safety switches / circuit breakers, 24VDC PSU.

The bigger the better. :slight_smile: My apartment (just two rooms + kitchen, 52 square meters total) fills up a single ABB UK540 box (56 modules) only with AC breakers, RCDs and consumption monitor. The whole install, with all the low voltage stuff, takes three of these boxes, mounted on top of one another. One more box with all the breakouts (TV, doorphone, Ethernet) and smart home HW and one more box hosting 12V power supplies for the whole system. These are the largest consumer-grade boxes i could find. Another advantage is that all the DIN mounts and faceplates can be removed, so you can leave a bare empty box, this is preferred for low voltage because the majority of the HW isn’t DIN-mountable.

Here is description of these boxes, for your reference: . I don’t know if they are available in Australia, OTOH; you may use American standards which i, frankly speaking, don’t know; i only know they are very different from european ones; and somebody might even think they are too restrictive and outdated.

If i was building the whole house, i’d go with a dedicated server room with a proper 19" rack, frankly speaking. This would give me a to-o-o-o-n of freedom.

  • If you centralise lighting to switch board how do you handle dimmers? Any good suggestions?

First of all, don’t centralize. It will be a nightmare to install and cabling would cost a fortune. My setup is distributed; it uses one modbus relay (3-4 channels) per room. If you think well, there are plenty of places to hide the hardware. Think furniture, wardrobes, kitchen closets, etc. These modules sit on a single modbus line; it’s just one cable. Should you choose another technology (e. g. CAN, KNX, whatever), the idea stays the same.

As to dimmers… Frankly speaking, oldstyle dimmers, which plug in instead of a conventional switch in a series with the bulb, completely suck (IMHO) with modern lighting. If you want a proof, go to a local IKEA and play with the demo stand. You can’t dim down below 50% (and 50% is still pretty bright), so that’s useless. I’d say, if you want good dimming, your light sources have to be made with the proper support. The modern LED light source has a built-in power supply; and a good dimming effect can only be acheved if the power supply has such a function. I. e. you don’t try to cut the power to it; but it has some kind of control input; and adjusts LEDs accordingly.
One example would be Hue bulbs. Many modern LED chandeliers are sold with RF 430 mhz remote controls; they can dim and change color temperature; you could use an RF transmitter to control them from the openhab. But there’s a drawback: if someone changes the state with an original remote control, your smart home system won’t notice it because the RF channel is unidirectional. A good solution would be to replace the built-in PSU of such a chandelier with some other model, which supports e. g. 0-10V interface, but unfortunately i don’t have a success story here. This market looks like has just started developing.

  • I plan to use Synology NAS as OpenHAB platform. Better to use Rasberry PI?

I don’t know Synology’s capabilities, but Java is a pretty hungry thing. Initially i tried running on 2GB Orange PI, that was slow and problematic; eventually i upgraded to rasbperry pi IV 4GB RAM.

Also some time ago i had some arguments here; and basically i was told that an RPi is a toy; and a “real server” would be far better. You know, if i had my personal family house instead of a small old apartment; i’d do just that. You can easily afford a small room with a huge industrial grade switch box on the wall and a 19" rack; UPSes and other stuff.

If you’re interested, i can share some photos of the system and good solutions i found.