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I bought a Wifi enabled light switch to smarten up my living room but i cant figure out how to wire it.

Here is the back of the original switch: rear plate of 4 gang lightswitch

And here are the wires from the socket: Wires in light switch socket

Finally here is the new wifi-enabled lightswitch: wifi enabled light switch back plate

As you can probably see there are 5 wires, 1 black and 4 red. One of the red wires has some green shrink wrap attached.

Is it possible for me to wire this switch?

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You probably cannot use your new switch there because there is no neutral in an old style "switch loop".

One of those 5 wires is permanent-live and was connected to "com" (common) on the old switches -- it now needs to be connected to "Live in" on the new switch. The other wires need to go to L1 ... L4 on the new switch. Unfortunately, you don't have a real neutral, that would be a 6th wire (plus nowadays a 7th CPC/earth/ground).

It may be that the black is permanent live.

If you have a voltage tester and an onlooker with the emergency services on speed-dial you can temporarily isolate all the wires in separate positions in terminal blocks then turn on the lighting circuit breaker and use the voltage tester to identify permanent live.

Then reconnect old switch and get quotes for running new wiring through the walls


Footnotes.

CPC = Circuit Protective Conductor. What the UK regulations now call what used to be called earth in the UK (which is mostly called ground in the US).

Your new switch is not legal to use in the UK because it is not CE marked.

How a 240V light switch gets FCC approval I don't know, that FCC mark seems suspicious. It probably only refers to electomagnetic emissions testing.

2A per gang seems low to me. Your old switches are 10A rated on a 6A circuit. I'm not sure it is legal in the UK to use a 2A switch on a 6A circuit. If a cheap Chinese LED light bulb fails short passing say 5A, the circuit breaker won't trip and your switch wil be overloaded and there is a significant chance it will catch fire. Using a 2A switch on a 6A circuit does not allow the breaker to properly do its job of saving you and your family from death by toxic smoke inhalation at 3 a.m. as the property burns down under you.

Those exposed clamp-screws on the new switch are unusual. UK switches mostly have all of the live metal parts recessed behind insulating plastic casing (see your top photo). I don't know if those exposed screwheads are legal.

Since my level of concern has been raised, the fact that the label doesn't fit the recess on the case now makes me worry about the general standards of design and workmanship in the factory where that was made. Was it very cheap?

It will probably work but if it burns your house down, your insurance company might have grounds for refusing your claim.

Personally I would take that new switch to Trading Standards.

What should you report to Trading Standards

You should report a company to Trading Standards if, for example:

  • they sold you unsafe or dangerous items
  • they sold you fake or counterfeit items

It's the sort of thing which Big Clive likes.

  • there are 4 reds not 5, the black was connected to com. When i couldn't figure out how to wire the switch i wired it back to the way it was before. – Jacxel Aug 11 '18 at 12:38
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    @Jacxel - It sounds like the 4 reds were a switch loops feeding back to the four lights and since the black connected to COM on the old switch that it is the LIVE power to feed those switch loops. Unfortunately that leaves you in a pickle as there appears to be no NEUTRAL in the box for the smart switch. Most smart switches need a neutral to be able to operate. – Michael Karas Aug 11 '18 at 12:46
  • Clarity: when you say "L1 ... L4", do you mean "L1" on each of the four switches? (I presume that the "L1" and "L2" on each switch are just two terminals on the same end of the switch.) – Daniel Griscom Aug 11 '18 at 15:23
  • @Daniel, no I meant L1,L2,L3 and L4 marked on the new switch. of course the new switch won't work without a neutral but if you had a neutral that's how you'd connect the red wires to the new switch. On the old switches, L1 and L2 are normally open (NO) and normally closed (NC), they are not connected internally. This is different to the US arrangement where you normally use SPST (single pole single throw) switches. The UK always use SPDT (single pole double throw) even when not needed for what US call three-way switches (which UK calls two-way switches). – RedGrittyBrick Aug 11 '18 at 16:23
  • Whoops, duh. Old switches are going away. (Thanks for the UK electrical lesson for this US dude.) – Daniel Griscom Aug 11 '18 at 16:49

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