Triple Gang light switch replacement (UK)

Thank you both for the super helpful replies, it will teach me to just bash out a question whilst watching Eastenders without giving it enough thought. There is only so much Sharon Watts a man can bear but I digress…

So below is a picture of the current switch controlling multiple lights:

From left to right, the switches control:

Far left - On/off for just the lights in the porch. They are currently just spotlights within the porch ceiling, further picture below…
Middle - On/off for just an interior light inside the hall, not planning on making that smart just yet but if it’s easier to do then may well do so…
Far right - 2-way switch controlling the light at the top of the stairs. The light at the top of the stairs can also be controlled by a single switch outside one of the bedrooms. This might be trickier to convert as I guess I would have to do the same upstairs?

The house is a child of the 70’s so the wiring is slightly older than a modern home, I’ve taken a shot of the inside of the switch below:

These are the porch lights (there are actually three of them) as they currently stand, just spotlights. I haven’t removed the ceiling but I would imagine there is a transformer buried away up there but they could also be 240v lights. I don’t know without ripping out the ceiling (which is also planned)

Moving outside, we do have a crappy old mains spotlight that you can see in the shot below. I’m planning on replacing this with a smart floodlight instead so I’m now thinking maybe separating out these two ideas. Have the floodlight come on if the movement is detected around my car and have a second sensor for switching on the porch lights?

The pictures below are of the front of the house and a close up of the eaves over the front door. I’m also pondering an exterior light in the porch eaves but outside as we’re always struggling to see the lock when it’s dark…

So my ultimate goals here would be the following:

  1. Someone approaches the front door when it’s dark then the interior porch lights come on and a single spot under the eaves so we can see the door lock easily
  2. Retain the ability to switch the porch lights on and off (interior and exterior) via a “normal” switch. Thinking about the mother in law who is a technophobe.
  3. I work for a company that supplies a home smart alarm that has IFTTT and Smartthings integrations (I’m not going to say who they are as I don’t do name dropping) so maybe the floodlight should only come on when the system is armed and motion is detected. We have an IFTTT applet that can support that.

Hopefully, this is all helps and certainly sounds possible but I’d like to get this right as smart hardware is more expensive than a £4 light switch from B&Q.

Thanks in advance :slight_smile:

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You know you have some kind of wire hanging down from your drainpipe right? Needed to get that out the way first. I would come at this more elegantly than the other two posters trying to help, guess it comes down to experience. Your “crappy old mains spotlight” probably works very well, and is reliable right? Making something dumb smart I find preferable than spending more for something smart, “bespoke” but unreliable. Just get a micro relay module and stick it so the signal from the dumb motion sensor goes to it first before it goes to the floodlight, that way you’ll get notified and can automate when there’s motion outside, and you can control the floodlight from ST also. You could use the Sonoff Zigbee mini or a Fibaro relay.

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Aye the wire is on the list but I need some ladders. It got blown in the wind for the TV aerial that hasn’t been used in about 15 years :flushed:

The floodlight is gubbed though and needs replacing so might as well replace it with something more useful…

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Have a read, might inspire you in some way

Just don’t use a fibaro controler, a good option now is a magic home controler

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In the US as has already been mentioned you would replace each switch module with a smart one. (US switch modules are individually much bigger than UK/EU switches.)

In theory you could fit three smart micro modules behind the 3-gang face plate but in reality such modules are so big that fitting even one behind a standard UK/EU square face plate is hard work and more than one effectively impossible.

What you can do is fit the micro modules in the ceiling typically above the ceiling rose and from there link to the respective light switch circuit. These could be switch micro modules or dimmer micro modules depending on the light fixture. In the case of the outdoor light you would likely not want a dimmer. You could then link a motion detector via a rule so motion activates the switch. With the physical switch also wired in you would still be able to use it to manually control the light.

In terms of micro module brands since Aeotec now make the Smattthings hub their Z-Wave micro modules would be the logical choice but other brands may work. You might want to replace the light switch(es) with momentary ones - especially for dimmers but they would still look like your existing switch plate.

Another option would be LightWave-RF which is pretty much the only smart light switch available in the UK with 1, 2 and 3 gang variants. However it is only available in dimmer form.


What about the Yagusmart switches, I believe there is a no neutral version as well.

Otherwise there was a topic about Smart Switches in the UK:

@Phil_Williams, sorry for asking, but do you have a Hub or a Hub optional setup?


That might just do the trick, good find!

I have an Aeotec Smartthings hub so I’m flexible either way…

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I think I might just go for one of these you know as proof of concept. I can faff about with the motion sensors later

Worst case is I lose £18.99…

Very worst case is I electrocute myself :roll_eyes:

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Those have become quite popular, they are a rebrand of a Tuya model so you may also see the same device sold under other brand names.

Straight out of the box only one button will work, you may need custom code referred to in the other links you’ve already been given in order to get functionality of all three buttons. (This is typical of smartthings regardless of the brand, the base platform just doesn’t handle multi button devices very well.)

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Hmm yep that’s a consideration. Just reading @jelockwood post again I’m now flip-flopping and considering the micros switches instead.

I’m gonna have to sit down outside of work and plan this out I think…

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Custom code is easy, you basically just copy and paste code that somebody else has written into the cloud interface to your SmartThings account.

The following FAQ is old but will give you the terms, concepts, and basic approach. ( The topic title is a clickable link)

The problem is we have not yet been given any details about how custom code for Z wave or Zigbee devices (what smartthings calls “hub connected devices“) Will work once the transition to the new architecture is complete. so there is a risk in investing heavily in something which requires that kind of custom code at this time. :thinking:

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So I’m gonna ask a potentially stupid question here…

Say for arguments sake I got the yagusmart 3 gang switch but for the time being only set the first switch to be smart for the porch lights.

Would the othe two switches still behave in the same way as a dumb switch until I sort out the custom coding?

I think so, but I’m not 100% sure. Ask in one of the threads where people are using that model, they should know.

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Actually this appears to be worryingly simple.

No harm no foul, I’ll give it a try.

Really appreciate the advice :pray:

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Notice where that person says they only saw one parent and one child. That means only one of the buttons was working. :disappointed_relieved: If you read later on in that same thread you’ll see that people had to use custom code to get all three buttons working.

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If you want to leave the other 2 switches I’d use a sonoff mini. This is in effect an inline relay which you can wire above your pod lights in ceiling and connect the two wires going to the existing switch to the switch contacts on the mini and hey presto you have smart lights that can also be operated by the existing light switch and they cost less than £10.


Yes, they should, the only complication really is your actual 3rd 2-way switch. By looking at your picture, that 3 gang switch is a 3 gang 2-way switch and nothing like that exists in smart. There are modules what you can fit behing switches, but they are max 2 relays. Those can be used with 2-way wiring.
There are options for 2 or 3 way setups as well with that kind of modules where only 1 switch/module controls the power and another one is mirrored.

The Yagusmart and many similar Tuya wifi and zigbee switches offer a convenient way to be able physically control from a switch, just by replacing the old switch with a smart one. But for 2-way, you need another switch installed at the other location and operate as a button only. Unfortunately at those setups only switches with neutral wire works, because the neutral wire-free smart switches need a physical load to operate.

Otherwise regarding electrocution, the UK has quite strict rules regarding electrical work done by only licensed electricians. (I lived there, saw that. - Rented a flat, the landlord did some renovation in the flat just after I moved in. Electric work as well, new fuse box. One day I saw that the seel of the meter from Scottish Power is missing. I asked the electrician, why he hasn’t mentioned this to me before, that something had happened. He told, that one of the cables just had fallen out from the meter so removed the seel and fitted the cable back… No comment! — It cost me a meter replacement after that…)

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The good news is the accessory/auxiliary smart switch does not have to use a physical traveler wire the Way a dumb switch does. So you can get around this simply by using any switch that can communicate to a smartthings account, even a battery powered switch, and use that.

The accessory switch sends a message to the hub, The hub sends a message to the master, the master controls the fitting. It all works and it should be ok with safety code since it’s only an accessory position, although of course you should always check with your local jurisdiction.

There are even some options that will work when the hub is not working. So I’m less concerned about this aspect of this particular project. That can be solved with a “virtual two-way.“ :sunglasses:



Just to iterate - this is still running well in my son’s room since I sorted this. Just download the code in that thread and it will work well. Only 2 of the three switches are wired in. I use the third to operate a smart plug for his lamps with a zigbee motion sensor that turns them al off if no motion sensor for a period of time (normal for kids!)

  1. The law in the UK allows you to change your own switches in the UK.
  2. The way a 2 way light switch is wired in the UK, means one switch will have a live connection and the 2nd switch will have the return to the light so you have to use a 2 way switch at both and the only ones I’m aware of that will work in the UK are lightwaverf but these are £160, plus you will need the additional lightwaverf slave switch at the other switch. These do work with smartthings as there is a native skill but not sure if you still need the hub (as I’ve got their hub too).

Thats why I made the suggestion I did with the sonoff mini. Value for money and effective.

Sorry I didn’t fully explain earlier.