DIY Doctor UK DIY Forums

Hi everyone, Basically, I am planning to replace the light switches in my new build house with smart switches and as the switch has WiFi built-in it needs constant power to work so will require a neutral wire I've pulled the back of the existing lightswitch and have a "Common" and "L1" 2 x Brown wires in Comm 1 x Brown wire in L1 would anyone be able to let me know if there was a neutral cable installed in the light switch? I have attached photos of them here. I notice the x3 blue cables with a cap on the end, would this be the neutral wire and if it is, will I need to plug all 3 of them into the new light switch? Thanks in advance.

I suspect the three blue wires in the wango connector are neutral, however you will need to check.

Likely you will need to connect all blue wires, some times however the wires are brought to the switch for you to use but not connected up, I suspect they are connected but can't assume.

You are lucky, the blue wires are the Neutral your new switch requires.

I would suggest you label the BROWN wires, and take another picture (With the labels clearly in focus) You may need this at a later date.

The "cap" as you called it, is actually a Wago connector. If you look carefully it has an "unused hole" with the electricity OFF push a blue wire into the unused hole and connect the other end to the Neutral of your switch.
Then you can connect the brown wires of your switch to the correct terminals (You did take that other picture didn't you)

Once done, carefully put the switch back, make sure you don't catch any wires, then switch the mains back on and learn your new switch to your network.

Hi, Thanks for your reply. I already replaced my old light switch to the smart light switch today and did exactly what you suggest. After the job is done it worked perfectly until the new light switch sparked when one of the cable tightening screws touched the metal housing and circuit breaker tripped because I forgot to turn the power off :(

I lifted up the circuit breaker, at first all lights come back on all the rooms except the one I caused a pop later half of the upstairs lights stoped working.

I tried both switches back and forward a few times as well as turning the circuit breakers on and of randomly and I can see that the live cable is sometimes active and sometimes not, the old switch works fine when the cable becomes alive but the switch caused a pop not working at all.

I suspect I fried the new light switch which I don't care but I have no permanent power half of the upstairs light switch now ( some switches connected to same circuit breaker works fine ) I guess I broke the continuity in one of the junction boxes

I tried turning on and off all the circuit breakers ( RTC reset ) sometimes and somehow I managed the live cable becomes active but only intermittently. I wonder if there is anything I can try before I call an electrician? any advice will be greatly appreciated. Thanks in advance.

I would suggest you put the old switch back as it was and see what happens.

I did say "With the electricity off"

I should mention even electricians do not work live as you did. Electricity does not forgive, get it wrong, it will kill you