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Looped through light switchs


ash_scotland88
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Had an issue before where a live disconnected from a light switch, which meant some other lights stopped working, only recently learned that looped through light switches is a thing.

 

Hoping that others on the ground floor are the same I looked at the wiring of one. It's a 2gang switch for 2 seperate lights.

There are 4 red cables, (well 5 if the small live link cable is included). So it's looking positive that this is also a looped at switch?

Doesn't this make it really difficult to problem solve or attach a new switch if the cables aren't marked up?

And I'm guessing if there is no sign of a joined neutral in the back box I will have to find where the junction box is if I wanted to add an extra switch and light?

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2 hours ago, ash_scotland88 said:

Had an issue before where a live disconnected from a light switch, which meant some other lights stopped working, only recently learned that looped through light switches is a thing.

 

Hoping that others on the ground floor are the same I looked at the wiring of one. It's a 2gang switch for 2 seperate lights.

There are 4 red cables, (well 5 if the small live link cable is included). So it's looking positive that this is also a looped at switch?

Doesn't this make it really difficult to problem solve or attach a new switch if the cables aren't marked up?

And I'm guessing if there is no sign of a joined neutral in the back box I will have to find where the junction box is if I wanted to add an extra switch and light?

 

Why did I go exploring?! Found what I am presuming is the junction box. Rat's nest of cable as it's above the fuse box too! ?

Someone has ran an extra 2core (no earth?) To it, or from it, and has just left one side unscrewed allowing it be ran in. It (junction box) is using the old fashioned twist terminal connections, including a few other junctions in the same access hatch.

 

The two core appears to be a live and earth, have the neutral taped up as earth. There does appear be a neutral there but on first inspection not sure if there are enough for a supply and two lights worth.

 

I'll grab a pic tomorrow. Even though it's out of sight it's upsetting me to know that mess is there. But I suppose that's years of ad-hoc electrical work.

 

Promising that I found it, unsure how to proceed in the correct manner.

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^^ the above 2 posts give me no confidence you know what you are looking at or trying to achieve.  Be VERY careful.

 

Yes there can be a lot of wires the same colour in a light switch or a light fitting.  It is important you identify them some way before removing a switch so they can go back as they were. I have lost count of how many times I have seen on a forum "I removed the old light fitting.  I now have 4 red wires and 4 black wires, which one goes where please?"

 

It sounds like you have neither loop at switch or loop at light but all cables connected from a BIG junction box, and at the rime that used to be common, it was common practice to just twist all the earth wires together outside the box, sometimes over the top to make it impossible to even get the lid off.

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Cheers, I was half expecting different colours as a means of identification. Such as having one as yellow, but I appreciate this may be further confused as L2. But in counter to this there is yellow cabling used elsewhere but thats in a 2gang 2way switch - from memory.

 

The fact there appears to be no neutral (black) at switch wouldn't that suggest looped at switch?

 

I can rule out looped at light as I've only ever seen 2 cables at each light when I've changed the odd fixture so far.

 

Easiest thing; i'll grab pictures tomorrow evening.

 

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Here we go.

 

Rat nest

DSC-1075.jpg

 

Junction

DSC-1076.jpg

 

Switch

DSC-1078.jpg

 

Junction, presumable bottom conduit is down to switch.

Right conduit is to light1.

Then 2core and left conduit is anyone's guess without investigation.

 

(Hopefully got those around the right way since website rotated it)

 

Edited by ash_scotland88
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That is OLD wiring probably 1960's.  Conduit will be the earth, neutrals direct to lights looped light to light.  Live direct to switches looped switch to switch and switched L from switch to light.

 

The twisted connections are "Screwits"  No idea what the extra cable added does.

 

Honest opinion, your lights need rewiring, who know what the rest of the wiring is like.

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Got the wiring ok'd when the CU was upgraded, and had some dating of 80something for some of the ring mains.

But yeah, this hole is a cluster F.

 

Why will conduit be the earth when there is also earth cable? And you can see an earth cable going up the conduit and out.

 

Unless something else crops up I think I agree with your live at switches and looped neutral. Although I honestly only remember one neutral at the couple of lights I've changed along with seperate earth that disappears up the conduit and isn't a short link from light to conduit.

 

Inspecting what goes to the other light of the 2gang will rule out if that's what the extra cable supplies.

 

As a small extra bit of info the Chinese that used to install Chinese lanterns at edin zoo used screwits all over the place then wondered why they had loads of issues. Give me a 16a grelco/ trelco any day of the week!

 

 

(Also just because I am nosey green and yellow earth makes an appearance in 77 according to Google)

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It could be earthing is added later. I don't think ive ever seen so much earthing on plumbing before around the house.

I'm looking at my photo of the junction and now doubting myself that the 2core neutral is relabled earth and what ever the green sleeve is is from something else.

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If anyone is on the edge of their seat anticipation....

 

The two core is in fact twin and earth, neutral was hiding underneath. And goes to a light in the adjoining hall.

All earths and neutrals are connected in the junction box. Three neutrals, four earths.

 

 

Will try and wago that mess but anything I can do regarding the T&E and for power for an LED driver instead of just out the top?

 

And further question....

Planning on LED strip in this back hall  (attached to ceiling light down wall) and in the adjoining hall. This will be Alexa/hue controlled for timers etc, guessing regs say this still needs a light switch even if we don't have any requirements for it be manually controlled.

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