Incorrect wiring in switch

[whatlozziedid]

Hello, I’m hoping someone could give me a little bit of guidance. Our house is full of head-scratching things (you know, where you scratch your head and just wonder why on earth someone ever did it like they did! And I say that as a DIY amateur!) At the moment, I’ve been trying to get to grips with the oddities of our light switches. Most of them were wired incorrectly, so turning the switch off turns the light on. That sort of excellent stuff. All over the house! (Previous owners said they were not remotely into DIY so I honestly think someone paid for this to be done at some point…) I’ve corrected all of them. Now I’m scratching my head over something else!

It’s a 2 gang switch. The switch on the left currently does ‘nothing’. The switch on the right turns on wall lights and a ceiling light. I suspect it should be wired so that the wall lights and ceiling light can be independent of each other. I opened it up to have a look and I’ve attached a pretty poor pic of the set up. There are two grey cables (twin and earth? I’m still learning the terminology so forgive me), one looks like pre 2004 wiring and one post 2004 based on the colours. Two blue cables from each of the twin and earth cables (unseen in this pic) are joined together in what feels like a little plastic terminal which is wrapped up in electrical tape. Yellow going into COM (at the bottom of the pic) looks wrong to me. The yellow cable going into COM is the switch that currently ‘does nothing’. Both earth wires are drawn in together into the switch’s face plate although in this picture it looks like there is only one. The back box is metal but does not have an earth wire connected to it.

Is it the case that the red and yellow cables running from the lights into the switch should be changed over in position? Red to COM and yellow to L1? As far as I know, this is one way switching as I don’t believe anything wired to this is served by another switch. What about the small red wire, should it be moved? Or should it be a different colour of wire? There is an outside chance one of these cables actually serves our kitchen light, but I don’t think it does. If it did it would then be a two way switch but I’ll cross that bridge when I come to it! Should the blue cables be separate and taped up as they are in a terminal? Should I be adding a length of earth wire to the back box, too?

Thanks for your time in reading all my waffle and hopefully I didn’t make a complete fool of myself by using terminology wrong!

[Someone-Else]

Believe it or not, there is no rule or regulation that says what colour wire must be used for what (Except the earth)

It appears that in the picture the red is live* The yellow is switched live to one light, and the brown is a switched live to another light.

The earth wires can either be connected to the back box, or (if a metal switch) connected to the earth terminal of the switch. Both become earthed when the securing screws are inserted and tightened.

* The short red wire is carrying live from one switch (You have two switches in the same package) to the other switch.

A switched live is so called because when you operate the switch, the wire becomes live.
If you have a light that does not work, I would suggest you check the connections at the light.

How are you testing anything? You may want to read my signature.

Twin and earth has two cores and an earth. Usually brown and blue.
If it has Red, Yellow, Blue and earth OR Black, Brown, Grey and earth it is called a 3 core and earth.

[whatlozziedid]

Thank you. I do need to buy a tester and I won’t go messing about with things again until I do. I don’t have any lights that don’t work (yet!) just this one switch that does nothing, presumably because live and switched live are in the wrong places.

[Someone-Else]

presumably because live and switched live are in the wrong places

Nope.

You can swap live and switched live as much as you like, does not matter.