What’s going on here then?

[Boing89]

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.

 

[Strima]

That looks more light a light switch not a socket?

 

[Boing89]

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]

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]

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]

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]

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]

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]

View attachment 48337
best have a look see.

Got you, thanks for your help.

 

[Boing89]

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]

@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]

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]

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]

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]

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.

 

[Boing89]

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.

Now’s the time to sort compatability I suppose. I’m working away for a fortnight so I’ve time to google what goes with what. I’ve already bought the light but not the lamps to go in it. It takes wee G9 capsule lamps according to the box. If I can get a neutral in I’m putting it on a dimmer, otherwise it’s going to an on/off switch.

 

[westward10]

I suspect that wiring is original, early 1970s. You are not going to get another plastic insert like the broken one so a repair may be possible. Fitting a deeper back box may not be that straight forward as the existing box is fixed to a wood batten.

 

[Deleted member 26818]

Could be earlier.
CPCs in lighting circuits became a requirement in 1966.
The fact that the back box has both plastic blocks and an earth terminal, suggests that it was designed for use with either system.
The single colour earth sleeving suggests pre 1976.

 

[Boing89]

I’m not frightened at doing a little bit of damage at this stage. I’m quite confident at making good afterwards nowadays.

 

[Boing89]

Could be earlier.
CPCs in lighting circuits became a requirement in 1966.
The fact that the back box has both plastic blocks and an earth terminal, suggests that it was designed for use with either system.
The single colour earth sleeving suggests pre 1976.

The house is Victorian so it wouldn’t surprise me if it was earlier. I found an old cable with a metal (lead?) sheath instead of PVC in the wall. Any ideas on how old that was? It was connected to an old brass light fitting that had been covered over with plasterboard at some point and left loose under the floor at the other end.

 

[coolsparx]

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.

There were some dimmable CFLs available but rare.

I agree with the Varilight V-Pro dimmers or modules, however I have just had to return 5 which didn't dim out of the box & 1 which failed to dim after a couple of hours, so don't know if they have a new batch problem.

 

[l4urence]

There is an inventor chap selling a backbox saver - effectively a new threaded nut held by a sleeve on the existing lug - designed for stripped thread - the lug needs to be there. I keep a couple in the toolbox. worth looking at, might be suitable? Fix a broken screw thread in your metal back box. Raise, tilt or lower a socket faceplate - https://backboxsaver.com

 

[westward10]

I have used those very expensive for what you get but worth the money if the back box cannot be replaced. Don't think they will fit the OPs box though.

 

[DjMadness]

Hi

I don't understand your shocking reaction. What part you've considered as weird or hard to understand?

The green wire fixed to the metallic box refers to the ground path. The black wire is looped from first conduct (origin like MDB) to the second conduct (where he goes to neutralize sets of lights or whatever bar nodes).

The two red wires are first the live (originated from MDB) the other is its return to feed the lighting set: dimmed by an external rotary mechanical shaft or equivalent, the live is shrank by magnitude (the POT sign on the return indicates a voltage divider that arrcodingly lights react)

What part of above writings you found strange?

As for the broken lug, you can use a rotary SDS drill to fit 3.5mm to 5mm screwdrive holder past the back of the box, then once installed you use 3.5mm to 5mm screwdrive but longer than the one not broken for like max 3cm

Dj