How to wire/plan whole extension zwave/smartthings automation? (UK)

I am planning an extension and want to use zwave automation to provide control of lighting, blinds, opening rooflights etc. At the moment I have around 20 different items or lighting groups/circuits to control for a large kitchen/diner/lounge. Given this is all new build I am wondering how I design the wiring and the positioning of zwave relays etc for the extension.

  1. Is it best to site all relays on a din rail next to a new consumer unit ? This seems attractive for maintenance and access. However I am concerned this would mean running cables from all physical wall switches in the extension back to this din rail as well as all the power to these 20 devices. This seems like a massive amount of wiring.

  2. Is it best to site relays behind the switches ? But some switches will be 3 or even 4 gang switches and this would seem to need 2 zwave relays somehow fitted into the switchbox.

  3. Is it best to site relays near the device (e.g. Blind, ceiling light void) ? But this doesnt seem to make for easy maintenance access.

  4. Do I need to mix and match the 3 above approaches ?

I would be grateful for any help, advice or pointers to good information sources. I fear it will be impossible to find an electrician that is familiar with designing zwave automated circuits and so feel I need to try and come up with a design myself to give to the electrician to cable up - first fix/second fix etc.

(PS I wanted to retain physical wall switches as the wife wont trust a purely wireless system, but maybe I should sacrifice some physical switches in favour of virtual/associations).

Thanks for any help, I am new back to this community after 2 + years absence.

1 Like

Oh. Also should I adopt a 3 wire cabling design for the extension so I have more choice of zwave relays/switches etc that I could use going forward (or just stick with traditional UK 2 wire design) ?

worth a read:


Sounds like an exciting project!

Definitely 3 wire, as it will give you many more choices in devices, both now and in the future.

And definitely keep some physical wall switches, in fact you may be required to do so by local safety codes. You do want to make sure that if emergency services has to come to the house there are ways to turn the lights on in the extension even if the home automation system is not working or emergency responders are unfamiliar with it.

@anon36505037 is in the UK and Has now done Two full houses with zwave kit, one retrofit and one new build, and should have lots of advice for you. :sunglasses:

You can start by looking at his most recent project here (the topic title is a clickable link)


@JDRoberts has hit the nail on the head, as usual.

UK resident here. My approach has ALWAYS been to keep physical switches, and that’s the primary reason I love the Fibaro kit. Incredibly reliable, local control, second switch input for extra flexibility. Never take away controls, always add.

Since you’re wiring from scratch, follow these guidelines:

  • Always use 3-wire + Earth cable between the switch and the first fitting. Although Dimmers don’t require a Neutral, they work better with one and it gives you the flexibility to use relays if required
  • Fit backboxes as deep as you can and put all the modules at the switch location. 47mm backboxes are ideal - lots of room to move about inside. Also, having the modules at the switch location is preferable for maintenance, and because you can utilise the S2 input for additional control. But, putting them in the ceiling is possible (and you can always mix and match the two approaches) if you are in a bind with a particular circuit.
  • Do things in such a way that you can always convert it back to a non-smart installation if required. In my experience, most people are not willing to pay extra for automation like this, so you’ll probably want to take it with you when you leave. If you do it in such a way that the automation becomes integral to the basic operation, you can’t really take it away.
  • I would personally avoid the DIN rail central control approach for the reasons above, plus the fact that it’s a lot more expensive. Fibaro modules in big back boxes with 3-wire cabling works a treat.

Thank you for the responses so far. I will take a look at that project.

I am also wondering what to do about electrical ring main sockets. I can’t remember the reason but I think I remember reading something that said it is difficult or impossible to produce zwave (or zigbee) uk sockets - which is presumably why there are none for sale. However I see there are some wifi controllable uk sockets now available. This would seem better than the somewhat clunky plug in smart adapters I have. So any comment info on these also useful. (I shy away from Lightwave RF as it would seem to be a legacy proprietary standard) Can wifi sockets be integrated into SmartThings ?

There’s no technical reason they can’t be created, it just doesn’t seem to be a large enough market because of the different socket styles and different countries in the EU.

There are a couple of options.

1) micros installed behind the outlet

Check the specs, but you may be able to use one of the zwave micro controllers behind the socket. I know people do this with the Aeotec nano, which is quite small. It doesn’t work in the US because minimum voltage requirements in most jurisdictions are 15 A and the micros can generally only handle 10 or maybe 13. But that may be sufficient in the UK where appliances tend to have a lower draw.

Plug In pocketsockets (zigbee or zwave)

There are quite a few plug-in pocket sockets, which are popular. These are available in either zwave or Zigbee.

3) new line Aurora AOne? (Zigbee)

There is a new zigbee line which was just certified as compatible with SmartThings, called Aurora Aone. They do make a zigbee dual in wall receptacle, but that particular one has not yet been certified for SmartThings and I’m not sure if it will work. Because it’s a dual device. Also, they are only intending to sell them through wholesalers, although a couple of the stockists will sell to individuals, just at a higher price. More about this in the following thread:

Some Aurora AOne Zigbee Devices added to official list (UK for now)

4) coming soon? Fibaro zwave in wall outlet
Fibaro has recently announced a new in wall zwave socket for the UK, but I don’t know anyone selling it yet. It could be worth waiting for though. :sunglasses:

5) WiFi options

As far as Wi-Fi in wall outlets in the UK, I don’t know of any that have official integration with SmartThings. Anything that works with IFTTT can use that as a “man in the middle“ and that tends to work quite well for outlets.

Here is the FAQ for that:

FAQ: WIFI Devices in ST? How can I integrate a WiFi or Bluetooth device that isn’t on the official compatibility list?

You may also want to check out Den -

Currently doesn’t integrate with anything, but there are rumours of APIs coming. Down side is that it needs an additional proprietary hub from Den.

Stooshire45 possible integration of DEN products is most welcomed news.
Thank you for sharing and I’ll hold off buying replacement switches in the hope of a DEN solution.
(I’ve been using Logitech Pop switches for the last few years. They work well for me until, someone switches off the wall mounted light switch. Small plastic bridges preventing ‘accidental’ use of wall switches helps but not that attractive. Den looks like the perfect solution.)