I am replacing a dimmer with a smart one. Can I do some clean up in this back box?

[Chaoscontrol]

This backbox in my lounge has an old dimmer switch with a metal plate. Since it has no earth I was recommended to replace it, plus I want to use smart switches all around anyway.

I got my new smart switch (no neutral) but it's quite thick and there's a lot in this back box.

This back box has 2 red wires connected to the dimmer, and then a yellow cable connected from the switch to a joint covered with tape, where 3 more red cables end. No clue what that joint controls. There's no extra lights anywhere. If there was way before we bought the house, we don't know where and don't plan to use them.

My questions are:

• Is the yellow cable doing anything? Can I remove it to remove clutter?
• Is there any way I can clear some space? For example disconnecting the joint and taping each cable individually? Or is that really bad practice? (worse than leaving the joint there anyway) At the moment there's no way my switch fits here. I'm thinking on 3D printing a surround plate + spacer to add thickness to it, but it will need quite a lot of extra space and will look bad.
• All cables in there are red. Any other switch in the house is colour coded, it's just this one. Can I mark one of the 2 red cables being used with black tape that I have? Which one should be marked? The one coming from the light, or the other one?

Many thanks!

 

[Murdoch]

You need a 1 gang spacer to fit between the wall and the dimmer

like this

https://www.toolstation.com/schneider-electric-lisse-spacer/p30687

 

[Chaoscontrol]

You need a 1 gang spacer to fit between the wall and the dimmer

like this

https://www.toolstation.com/schneider-electric-lisse-spacer/p30687

Yeah, I'm aware of them. But the smart switch doesn't have a standard face plate, hence 3D printing my own. And as I said too, a single of those still won't get me enough space. That joint is bulky, and the switch is too.

Please help me with the questions.

 

[monkey5]

Proper way would be to chase in a deeper back box to be honest

 

[binky]

That joint is bulky, and the switch is too.

Please help me with the questions.

A Wago would be slimmer than choc block, but not massively so.

 

[Chaoscontrol]

Proper way would be to chase in a deeper back box to be honest

We just got the walls painted, so tbh there's no chance to do that at this point. As I said If I really cannot do anything else I will just 3D print a spacer large enough to allow it.

But can't I just remove the choc block and leave the open cables taped independently?
Also, what I'm really mostly interested is help with questions 1 and 3 tbh, as those are the ones keeping me from connecting this right now.

 

[Geoff1946]

If the "unused" wires are live then taping them would not be a safe way of termination. No-one on here can know whether they are live or not, so can't give the answer you would like. An electrician on the spot could test and possibly determine that they are dead, - or not.

 

[Mike P]

It looks like loop through wiring termination and no earth. It wouldn’t make to much mess putting a deeper back boy in. Use a multi tool and jest spend a little time on it,

 

[Chaoscontrol]

It looks like loop through wiring termination and no earth. It wouldn’t make to much mess putting a deeper back boy in. Use a multi tool and jest spend a little time on it,

I don't own a multi-tool and honestly don't want to spend any more money on it.

Can you tell me what to do with the yellow wire though? With that I can at least proceed to connect the new switch and stop the old buzzing.

 

[BorisJ]

The yellow wire is there for a reason. If you disconnect it you will find out why. Likewise the red wires are connected together for a reason. If you separate them you will find out why.

 

[peterspurs]

Is there a cpc earth wire there?

 

[Andy1733]

Imo you should chase the wall deeper and make more room for the cables. If it's recently been decorated you should have some spare paint for touch up.

Several good solutions given and your choosing ignore them.
3d printing it is....

 

[Chaoscontrol]

The yellow wire is there for a reason. If you disconnect it you will find out why. Likewise the red wires are connected together for a reason. If you separate them you will find out why.

Super useful, thanks.

This back box is a mess, starting by not being colour coded and not having an earth. The previous owner surely messed with this I since I have no clue what's there, I'm pretty sure it could be cleaned up. But wanted to seek more advice.

 

[Chaoscontrol]

Is there a cpc earth wire there?

No there isn't in this specific box. Other switches around the house have it though, and are colour coded too.

 

[Chaoscontrol]

Imo you should chase the wall deeper and make more room for the cables. If it's recently been decorated you should have some spare paint for touch up.

Several good solutions given and your choosing ignore them.
3d printing it is....

The back box is attached to a conduit and I'm not handy enough to detach that. Plus, I don't have any tool for chasing. Plus with the cables there, not sure how to detach the box.

 

[Murdoch]

OP the lack of cps or Earth isn’t a great sign - how old is the property ?

it could be that the conduit is connect to earth BUT that would need confirming.

changing the back box will not be easy, or neat in my experience

 

[Chaoscontrol]

OP the lack of cps or Earth isn’t a great sign - how old is the property ?

it could be that the conduit is connect to earth BUT that would need confirming.

changing the back box will not be easy, or neat in my experience

60s.

It most probably doesn't have an earth in the conduit. We even found one socket without an earth (luckily just one). I added it myself in the conduit before the plastering happened.

It's the same with this switch. All other ones have earth, but this specific one had some messy work done at some point. I'm not at a stage to rewire. I just want to connect the smart switch there (which I just did).

I tried disconnecting the yellow cable but then there was no voltage drop between the wires. So I guess that the yellow cable is the one feeding the lights. However now my LEDs flicker like mad. They are dimmable and this smart switch is supposed to be trailing edge.

 

[Murdoch]

a 1960’s home is probably nearing the time rewiring is envitable

 

[BorisJ]

Super useful, thanks.

This back box is a mess, starting by not being colour coded

What colour coding would you expect?

 

[Chaoscontrol]

What colour coding would you expect?

Not an expert, but other lights I connected had blue and brown. Plus I'm colorblind. And sockets too.

Just not everything red. There's no way to know which cable comes from the bulb and which one doesn't.

Anyway, I managed to connect the smart switch and is working perfect. Now I just need to figure out what to do with the mess or get a chunky spacer in there.