I will be looking at adding Phillips Hue Bulbs soon and have been looking into Smart Light Switches to replace the ones I currently have, however, I have an issue
All of the Zigbee Light Switches that I have seen, i.e. the SONOFF SwitchMan Zigbee Smart Wall Switch | ZBM5 80/86 Type require a Deep Back Box of approximately 40mm.
Unfortunately, the Back Boxes, I am in the UK, I have checked all seem to be approximately 18mm Deep.
I do not think it is feasible, or even possible, to replace the Back Boxes with Deep Versions.
Definitely feasible & possible, but messy. I had to replace a couple of mine to accommodate smart switches. Remove backbox, chisel out the back, replace with another backbox. Just checked & Screwfix have boxes going all the way up to 47mm.
Otherwise your options are somewhat limited if you want to keep the existing setup:
Use a spacer (really ugly imo).
Assuming you have access, install a smart module (like the Shelly) at the ceiling rose where there should be live, switched live & neutral wires.
I did not consider putting the Shelly in the Ceiling Rose of the Light Fitting, I was thinking it had to go behind the Light Switch which with an 18mm Back Box is not happening.
The live & switched live wires which are behind your switch should also be in your ceiling rose. Best thing to do is call an electrician (or someone with decent electrical knowledge) to confirm before you buy a bunch of modules.
Check out some battery powered or even switches powered by the force you exercise on the button to power the command:
If you want to use the switch as ZigBee router, you need it to be powered though. My personal experience with ZigBee wasnāt great until I added routers (as it happened in the form of switches).
Actually it should fit if you just use it without the āholder adapterā. Common Shelly device is only 16mm thick.
You need gen4 device though if zigbee is required.
Thereās no way to fit a Shelly behind a light switch with only 18 mm. The light switch itself is taking most of that space for sure. And even with 40mm or even 60mm deep boxes itās not exactly a ton of space, because there are also the cables themselves.
Iām also not convinced about the ceiling solution, but that depends on how the cables are routed. You would need constant power (that means 2 wires) plus 2 wires to the light switch).
Battery powered ZigBee switches are indeed an option, but in my experience they are all universally meh compared to the traditional light switches. They donāt have the normal click, they are more like mouse buttons, which is just not nice experience compared to the traditional clicky switches. They are harder to find without looking and you will more often not be sure if the click was registered or not. And Iām talking even about the supposedly premium ones, like Phillips Hue.
Therefore the solution of using existing light switches with a shelly or something similar behind is superior.
OP is in the UK. Most UK houses have all the wires you mention in the ceiling rose.
What they donāt usually have is a neutral at the switch location, which means that in addition to the back box issue, they will also have to figure out where to pull a Neutral from.
No-neutral modules donāt work with decoupled mode, which is required for smart bulbs, so the only realistic option is a ceiling install.
