Wiring 3 Way Light Switches So Permanently On? (UK)

Hi all,

Probably posting in the wrong area so feel free to move.

I’m after some help from the ever knowledgeable ST community.

I have 3 x 1 gang light switches controlling 1 ceiling bulb. I want to blank off the light switches and have adhesive mounted battery operated zigbee switches stuck on the blanks that will control a smart bulb hanging from the ceiling. I therefore need to connect the wires inside the back boxes so the light fitting is permanently on. Unfortunately I’m not sure of the right way to do this.

Please use nice and simple terminology as I’m not an electrician.

UK based in a house that was built around 10 years ago if that matters.

Thanks in advance :slight_smile:

Unfortunately, my understanding is that this is not legal in the UK unless these are just accessory switches for a two way.

At least in England, safety code requires that there be at least one master switch in the room which controls the current directly to the fittings in that room. This has previously been discussed in the forum by people who live in the UK and know much more than I do.

( The US does not have the same requirement in most jurisdictions with the exception of attic spaces, which is why you will see so much discussion in the forum about bypassing the switch. But that option is not available to UK members.)

Instead, the usual solution in the UK is to build a little wooden or plastic case which fits over the top of the existing switch and can be lifted up to access that switch. And then put your battery operated device on top of that. Some people print these with a 3-D printer, some just make one themselves.

That meets the code requirements and can be quite attractive if you put some thought into the design.

@Mikeyf79 or one of the other UK wiring experts might have more to add.

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I forgot to mention that you can often find these switch covers at Etsy shops. Here’s a not particularly attractive one to my eye, but it was designed to fit smartthings zigbee Button, so it will give you the idea.

You are allowed to terminate the wires within the back boxes as long as you can service them.
The first thing your going to need to do is mark each cable and take photographs of where they go in each switch to eventually put them back in case you move or just want to revert.
Next you have to work out how it’s been wired as there are a number of ways to achieve 3 way wiring. I’ve enclosed some pics below for info, these are the 2 most common ways.
Basically you need to find out which wire is permanently live and which wire goes to the lamp. All the rest are redundant, so if they are in the same switch backbox simply connect these 2 and hey presto. That way all the others can be left as they are and then you only need to revert one switch in the future.
To find out which is permanent live you’ll have to use a meter or detector. BE CAREFUL AS IT IS LIVE -

From your pictures I’d say pics 1 & 2 contain the permanent live and wire going to the lamp and your wiring is per diagram A. But you will need to check.
If that’s the case you will need to use one of the other wires to be able to connect the live to the bulb wire.

Diagram A


Diagram B

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But I have to ask, why are you doing it this way?

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Agree with Mike F, this is a 2-way plus intermediate configuration.

The middle picture looks to be where the live from the ceiling rose and switched live return to the bulb are connected. These will be in S1 and S2 of the switch. Brown should be the live and the blue with brown marker the switched live return. You should be able to see that they both come from the same twin and earth cable. Connecting these two should deliver what you want. HOWEVER, please confirm the connections with a meter BEFORE changing anything and ideally get an electrician to do it for you.

I also agree with Mike F that this is not the best way to do it. IMO keep the standard bulb and replace the switch with a Smart switch or a module. You can then add additional smart buttons and use automations to have them control the light. I would still urge you to get an electrician to make the changes though.

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Thanks everyone for your replies. There are a number of reasons why I don’t want to proceed with your suggestions of alternative ways to achieve a similar outcome which I won’t go in to now. I know there are a few ways around this and I have considered them all but they don’t quite fit for various reasons. My final switches have arrived so I’ll be giving this a go shortly. I have a multimeter so will be carrying everything out safely. Thanks again for your help :slight_smile:

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