What’s going on here then?

Boing89 · Mar 15, 2019

So, I’ve just had my living room plastered and the plasterer asked me to loosen the dimmer switch for him. When I went to put it back on the wall I He-Manned the screws back in and broke the lug on the left hand side of the pictures (as an aside are these available to replace or am I going to have to replace the backbox in my freshly plastered wall?) On closer inspection after my heroics I have 2 T+E cables with only the reds in use and 1 black cut right back and the other left floating but not stripped so it’s never been put anywhere. Having lived in this house 2 years now I’m starting to discover the previous owner had his own “unique” way of doing things. Do I need to be worried about this (I was only expecting a switch wire as there are no other switches for this light).

My background is on 3 phase machines and small to medium generators so I’ve a good idea what I’m doing if everything seems normal but this has thrown me. I’ve a decent multimeter in the van and I’m more than capable of using it. If you can shed some light on this or suggest some tests to help me work out what’s going on here I’d be most chuffed.

[ElectriciansForums.net] What’s going on here then?

Strima · Mar 15, 2019

That looks more light a light switch not a socket?

Boing89 · Mar 15, 2019

Strima said:
That looks more light a light switch not a socket?

It is a light switch, I’ve no idea why I put socket, I’m going to edit it now.

telectrix · Mar 15, 2019

cut round the box with a multitool and a cheapblade, as the blade will soon wear out.then you can remove with minimal plaster damage. chop a bit deeper, fit 25mm box. fill any damage. rewire dimmer as it is but without all that exposed copper.

Boing89 · Mar 15, 2019

telectrix said:
cut round the box with a multitool and a cheapblade, as the blade will soon wear out.then you can remove with minimal plaster damage. chop a bit deeper, fit 25mm box. fill any damage. rewire dimmer as it is but without all that exposed copper.

Thank you, I’m going to change the light fitting when all the decorating is done do you think I’m going to find extra wiring up there or will it look pretty standard?

telectrix · Mar 15, 2019

Boing89 said:
Thank you, I’m going to change the light fitting when all the decorating is done do you think I’m going to find extra wiring up there or will it look pretty standard?

best have a look see.

ipf · Mar 15, 2019

Boing89 said:
Thank you, I’m going to change the light fitting when all the decorating is done do you think I’m going to find extra wiring up there or will it look pretty standard?

You tell us.....
It's awkward if you've not done it before...but that adjustable lug can be replaced. Have you still got the damaged one?

ruston · Mar 15, 2019

That lug looks an easy fix , it looks like the old plastic type . With your background tap it out the next size up and fix it back in , or go to a wholesaler and buy a single box with floating lug and fix it in place in the damaged box.

Boing89 · Mar 15, 2019

telectrix said:
View attachment 48337
best have a look see.

Got you, thanks for your help.

Boing89 · Mar 15, 2019

ruston said:
That lug looks an easy fix , it looks like the old plastic type . With your background tap it out the next size up and fix it back in , or go to a wholesaler and buy a single box with floating lug and fix it in place in the damaged box.

They’re just held in by bending 2 lugs on the backbox over them, the right hand one fell out and I put it back in. I just didn’t know if that type of thing was still available.

ruston · Mar 15, 2019

@Boing89 . If all else fails - drill , tap and thread the backbox 3.5 mm, and away you go. Drill far enough through to allow the screw a decent depth.

littlespark · Mar 15, 2019

The 2 reds are a live and a switch wire going up to the light. No idea about the 2 unused blacks.

However…. If you decide to change the light fitting, and go and get a fancy LED job... then your dimmer switch might not work and you'll need to get a dimmer that is compatible.

If you need to do that, then you will need a deeper back box. (i'm surprised the existing dimmer fitted on what's there!)
You may also need a neutral at the switch... which you may have if you can trace one of those blacks up at the light.

Makes you think this should have all been looked at before decorating, huh?

Boing89 · Mar 15, 2019

littlespark said:
The 2 reds are a live and a switch wire going up to the light. No idea about the 2 unused blacks.

However…. If you decide to change the light fitting, and go and get a fancy LED job... then your dimmer switch might not work and you'll need to get a dimmer that is compatible.

If you need to do that, then you will need a deeper back box. (i'm surprised the existing dimmer fitted on what's there!)
You may also need a neutral at the switch... which you may have if you can trace one of those blacks up at the light.

Makes you think this should have all been looked at before decorating, huh?

Well there’s no paint on anything yet and I’m handy with a filling knife but yes. Even if it’s not connected I should hopefully find one of those blacks back up at the light fitting and I can use it as a neutral. I didn’t even consider LEDs need a different type of dimmer. Is that just for dimmers or any switch for LEDs? Because a standard on/off and some nice lamps could be the way forward as well.

Boing89 · Mar 15, 2019

ipf said:
You tell us.....
It's awkward if you've not done it before...but that adjustable lug can be replaced. Have you still got the damaged one?

Half of it is still attached to the screw and the other in the box, I might even try a bit of superglue.

littlespark · Mar 15, 2019

A normal on/off switch is fine for any light, including LED.
CFL... compact fluorescent lamp... the little spiral glass tubes cannot be dimmed at all.
LED require an electronic dimmer, and there are so many different dimmers and different LED lamps, it’s trial and error to get ones that are compatible.
Varilight seem to be a good bet for any LED

Halogen lamps can be dimmed in the traditional sense using your existing dimmer. Slightly better energy efficiency than old lamps, but not as good as LED.