Can anyone tell me what the blue and yellow wires are? I know the red is the hot. Is the blue or yellow wire a neutral wire?

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  • 2
    What country are you in? That affects wire colors. Commented Apr 7, 2019 at 16:58
  • 1
    Each of those two switches controls something. Is that "something" also controlled by another switch somewhere else, i.e. Can you switch it on/off at either location? Commented Apr 7, 2019 at 21:24
  • Can you post a photo of the inside of the other switch location? Commented Apr 9, 2019 at 3:10

2 Answers 2


Won't work.

From the 3-core cable, and from the fact that all wires of each cable go to 1 switch, it's perfectly clear that this is a 2-way (USA: 3-way) switch.

And further, it is the switch on a "spur" line.

In this location, those three wires will be 2 travelers and a switched-hot. None of the wires are hot or neutral. So it is not possible to add a smart-switch here, except by greatly reconfiguring the entire circuit.

However, it may be practical to fit a smart-switch at the other 2-way location, depending on which wires are there. If it, too, is a spur, then smart switches will require a dramatic reconfiguring of the whole circuit, and to help you there, you'll need to supply a lot more information about what is going on inside the other switch box and at the lamp.


According to this chart, if you are in UK and red is hot (as you stated) then neutral should be black, and yellow & blue are hot wires.

It also looks like you have two identical switches, but more description - and/or a picture of the front of the switches - would help.

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