Shelly 1L - UK 2 Way Switch (3 Wires in each switch + earth)

  • Hello All,

    I am not sure about forum etiquette, so apologies if i have posted in the wrong place but i thought it would probably be best to start a new thread for this.

    I have purchased the Shelly 1L and Bypass for a 2 Way Switch, single light, setup and have fitted the bypass without issue. However, the wiring in both switches are as shown in the attached image and I have wired in the shelly 1L as suggested by Dimitar Dimitrov, and shown in the image below. Sadly though, at this stage all I can do is turn the light on/off via the shelly and the switch it shares a wall box with. If I then flick the other switch on/off it cuts power to the shelly and the switch in the wall box with the shelly.

    Unfortunately i do not know the circuit is wired in the walls, all I know is what i have posted above and that, before installing the Shelly, both lights would alter the state the light was in when flicked - regardless of the current state of the other switch or the light itself.

    Any help/insight here would be appreciated. All I can think of is that the light itself might be in between the two switches in the circuit and that putting a Shelly 1 in the ceiling with the light might work. However, I have the Shelly 1L already and would prefer to find a solution that utilises that if possible.

    Thank you all in advance and i look forward to hearing your suggestions.


  • Go to Best Answer
  • Hello, thank you very much for your message and willingness to help out.

    I have prepared a wiring diagram showing the switches and the lamp as best I can as I do not know how the circuit is laid out in the walls and celling. The original circuit contains Switch A, Switch B and the Lamp. Switch C is a switch for another lamp in a separate room, but I have included it in this diagram as it shares a wall box with Switch B. This diagram is as follows:

    existing wiring.png

    Photograph of Switch A before installation of Shelly device:

    Switch A.jpg

    Photograph of Switches B and C before Shelly device installation:

    Switch B + C.jpg

    I had attempted to install the Shelly 1L at the same location as Switch A, leaving the wiring as it was in the wall box for Switches B + C. I have since uninstalled the Shelly and so have not got a photograph of the device installed. However, the diagram below shows how I intergrated it with the existing circuit:

    shelly wiring.png

    Looking forward to hearing back from you and thank you in advance for your assistance.

  • My apologies for the delay between my responses, I have been at work.

    I have done some investigating and it would appear that the Live wire is coming in to Switch A and the Switch Live wire is from Switch B. However, I need to mention that the diagrams I have sent have Switch C and B labels mixed up. The switch labelled Switch C is what I have been referring to as Switch B in our conversations (including above) and the switch labelled Switch B is what I have been referring to as Switch C. My apologies for this mix up.

    Thank you again. I hope this makes sense. Please let me know if you require any other information.

    • Best Answer

    all good, I'm working too and so you have waiting time too ?

    No problem.

    When I'm understanding all right

    It have to be so.

    SwitchA is the place where the shelly need to be fitted.

    (I'm now using this pic)



    Disconnect Com and put it at L from Shelly

    From Shelly O a wire at Com

    Disconnect L2 and put it in Com too

    Disconnect L1 and put it at SW2

    A wire from L1 or L2 to SW1

    Switch C

    (If it are the same Colors perhaps you need to check)

    Disconnect L2 and put it at Com too

    So it's nearly your second pic, only Switch C med there to be changed

  • I have just installed the Shelly with the method you describe and everything now works perfectly! Thank you very much for your help, it is greatly appreciated. I have marked your answer as "Best Answer" already but please let me know if there is any other protocol on the forum that I should follow as well. Thanks again!