Wireless Switch for New Light in UK - Best Solution?



First time poster here - I’ve had my hub for a few months now and have been gradually switching things over to SmartThings in my home - lights (typically Tradfri, Lightify), TRVs (Danfoss), a few motion sensors (Samsung) to automatically turn lights on/off, a multi-sensor (Samsung) to tell me when mail has dropped into my outside postbox (still in progress). I’ve a development background so am also familiarising myself with handlers, smartapps, CoRE etc but haven’t yet started cutting any code.

I do have a very specific requirement that at first glance sounds like it has already been covered bythe many quality threads I’ve read here, but I’ve not managed to identify a solution that is right for me. So, I thought I’d ask. Here’s my requirements:

  • We are in the UK
  • We recently moved into a house that has a 4 meter high ceiling living area but that area has no ceiling lights - that part of the house has floor level 5A sockets with floor lamps
  • The boss want to add a couple of pendants to the ceiling and I want to be able to control those from SmartThings
  • However, we also need to be able to control the lights from a wall mounted switch
  • I have an existing powered wall switch i could expand/re-purpose if required (2 wire system)
  • We have access to the loft space above the living area and can get wired power to the pendants
  • However, there’s no non-destructive way of getting wires from the switch to the pendants
  • The solution can’t be internet reliant - I i don’t want to be in the situation where I’m away for work and my wife can’t turn lights on and off (ie. has to be local processing)
  • The solution could be internet reliant if the manual switch still worked during any outages
  • The pendant doesn’t have bulb fitments for bulbs can be ST controlled (ie, not E14, E27 etc)

Can what I’ve after be done with ST and the Fibaro modules or with another ST compatible module? eg, a Z-Wave notification switch (or behind the switch) and a Z-Wave relay above the lights with a smartapp controlling it? Or would that automatically make it cloud based?

I’ve read many posts here and articles on other sites (eg, vesternet.com) but haven’t yet found the right solution for me.

I’d rather not have to go down the Lightwave RF route or another non-open solution.

Or do I just need to accept that my plasterboard is going to get some collateral damage, run wires from an existing wall switch, and install a Fibaro module either behind the socket or above the light?

Any thoughts appreciated.

Fibaro Dimmer 2, Direct Association and Toggle/Momentary Button: Correct Setup?
Panic Mode and Direct Association
(Andy - United Kingdom) #2

You could use the Fibaro dimmer module which I don’t believe requires a neutral at the switch (dependent upon wattage levels etc)
Then you could use whatever pendant light fitting you want
the great thing about the fibaro modules it that they can be manually controlled with a normal light switch even when there is no internet.

One of the guys here is in the UK and have done his whole house with fibaro units @RobinWinbourne
Now that I’ve tagged him he will probably be along soon to advise.


HI @Cobra, how would the dimmer module control the pendant without the line between the switch and the pendant? Won’t i need both a controller at the switch and a relay at the pendant?

(Andy - United Kingdom) #4

Basically, you would wire the pendants in the conventional way then place the fibaro unit behind the switch (or at the pendant if nor room behind the switch.
The switch is then wired to control the fibaro… then the fibaro controls the light

The Fibaro is both controller and relay (sort of)

(MarkTr) #5

Does local electrical code allow for a light and the controlling switch to not be on the same circuit? I think the concern would be that someone wanting to do work in the switch box could cut power to the light via the breaker, assume there was no power at the switch, and then get zapped. Of course, people do things that aren’t to code all the time, but it’s something to consider.

Edited to add: code probably doesn’t consider a situation where the switch can control a light that isn’t on its circuit, I don’t know if many locales or the big councils like NEC/IEC have updated them to consider smart devices.

(Andy - United Kingdom) #6

The Fibaro replaces the switch in the circuit… so cutting power to the circuit will also cut power to the fibaro… leaving unpowered lights no matter what you do with the switch

(MarkTr) #7

As I read it, OP’s proposal was powering the switch from one existing circuit and supplying the lights from elsewhere.

(Andy - United Kingdom) #8

in the UK the lightswitch in effect just cuts the live wire from fusebox to pendant light.
I would expect this to be the same


HI @Cobra - I’m still missing something here. If the pendant is wired to the mains only, with no wire to the switch, and no fibaro relay, how can a fibaro behind the switch control it?

I can see the scenario with the relay at the light, and another controller at the switch controlling that relay (via ST) but I’ve not seen that setup proven anywhere yet.

Perhaps I’m missing something major here on how the fibaro modules work - electrical engineering is not my thing.

(Andy - United Kingdom) #10

Maybe it’s me assuming too much about your current wiring…
What does your existing lightswitch control?


Yes, that’s correct. There is no wire from the switch to where the pendant will be and it will be plasterboard-destructive to introduce one. I’d also be ok going for a battery operated wall switch communicating with a relay at the light. But my ideal would be

  • The hardware switch must work during internet outages. It would be acceptable to have to flip the switch a couple of times to get the power back on during an outage
  • Powered switch so no need to replace batteries
  • Ideally not cloud based to reduce latency and minimise the chance of “lost” messages from the switch to the relay above the light

Thanks for all the feedback.

(Robin) #12

If you have no wire link between the wall switch and the pendant then you’ll need to use Zwave direct association to keep things local and non-net reliant.

This will require two Fibaro modules, one at the switch and one at the pendant.

You would then link them to the hub AND to each other using the direct association feature.

Direct association also has the benefit of instant response over cloud lag.


It controls the existing 5A floor lights. I mentioned that as a powered wall switch would be ideal, but a battery operated one would be acceptable.

(Andy - United Kingdom) #14

this is where I was getting confused.
I had assumed that the wires from the lightswitch went to the area of the pendants.


Thanks @RobinWinbourne, that helps. Does ST support direct associations? I’ve not done much reading in this area yet, but I have read that ST doesn’t support some of the more complicated aspects of the protocols.

(Robin) #16

It requires a device handler capable of setting up the association, which already exists :smile:

Will track down the links for you.


Yup, thought that might be the case :slight_smile:

I hoping to not have to pay an electrician and a plasterer! The former is a friend and will do things at mates-rates and i’m hoping to avoid the latter.

(Robin) #18

Use this handler for the Fibaro:

It has association setup in the settings view.

This can also setup the associations:

Doesent need to be two Fibaros, could be any ZW5 device capable of association… you’ll need to read the manuals carefully if choosing alternative devices, but I confirm the Fibaro Dimmer 2 modules work very nicely in this setup… been there done that got the T-shirt.


Perfect, thanks @RobinWinbourne - some reading for me.

So it sounds like a dimmer behind the switch and the relay at the pendant is the solution?

Once i read through that, i’ll come back and ask about the actual physical switch. eg. What happens with the existing toggle switch in the case where the light is switched via ST rather than that switch. Can it then work as a true toggle (ie. up or down can mean on or off) or would it be best to replace it with a momentary switch.

(Robin) #20

No point having a dimmer module at the switch and a relay at the pendant… that would mean no dimming ability.

The Fibaros have a parameter setting to choose between keeping switch state in sync or not, so you can keep up as off and down as on. If the light is turned off programmatically you would need to toggle the switch off on to get it to turn back on.

Fibaros just use any existing dumb switch, module goes behind. If you go for a Dimmer (which i recommend) then it’s best to use a momentary (retractive / push-to-make) switch.

Even if you only want on/off, I still recommend getting the dimmer modules. They don’t need a neutral (unlike the relays), can be programmed to work in on/off mode, and cost the same, leaving options open for the future.