Wiring to light switch different than I have seen before.

[nisioptimum]

Was doing some work for a customer (just replacing a couple of damaged double sockets) and he said he had thought of changing the light switches because they were discoloured. The switch he showed me had a white twin and earth going into it and then leaving. The earth wire was unbroken sleeved in green and connected to the earth terminal those confirming one run of wire. The neutral was just cut with 2 very short ends, one so close to the white sleeving it was difficult to see initially. The live was just cut fed into common and L1. It all works fine and he has no problems. I didn't have time to look at the ceiling rose but have been trying to figure it out. Should have said single switch to bedroom light. I assume the wire in fed from the common and the one out is switch live but why run it in such a manor? Instead of one length of T+E there will be twice the length. It is not a problem was just wondering as I had not seen it before. I did suggest I did some insulation resistance testing to confirm the wiring was still upto the job and I would go back and properly inspect before changing the switch plates. I am sure lots of you will know straight away if I am completely wrong or not.

 

[MDJ]

sounds like a feed and neutral to the switch then a switch wire and neutral to the light, perfectly normal except the version you have mentioned sounds a bit rough and could do with reconnecting properly, otherwise unless I am missing something no real issue.

 

[trev]

Sounds like poorly done 2 plate. Nowt wrong with 2 plate wiring, not the way I'd do it but never mind.
Whte T&E sounds like LSF. Shudder, horrible stuff.

 

[Adam W]

Could have been that the person who did the 1st fix intended to run a neutral to the switch but then the person doing 2nd fix didn't like that idea.

 

[nisioptimum]

Sounds like poorly done 2 plate. Nowt wrong with 2 plate wiring, not the way I'd do it but never mind.
Whte T&E sounds like LSF. Shudder, horrible stuff.

No it is not LSF it is old white PVC Sleeve which is why I suggested the insulation resistance test to see if it was still OK.

 

[itselectric]

So are you saying there are two twin and earths at the switch but only the reds are connected and blacks are chopped short.

 

[nisioptimum]

So are you saying there are two twin and earths at the switch but only the reds are connected and blacks are chopped short.

Yes it is the same wire as the earth is unbroken folded over and connected to the earth.

 

[Richard Burns]

Quite often single core reds were used for the switch wiring and it may have been that this was the only method the installer knew of wiring the switch.
They only had twin and earth so ran that instead, only using the red core, as they would with singles; at least they earthed it.
White T&e was fairly common at one point and was the same as grey T&E, until they changed it make white T&E LSF.

 

[NickD]

It's all a matter of speculation until you've seen inside the rose.

 

[Badged01]

Of course it is until anyone actually sees whats there and where it goes to!

But based on the info given from the OP I think the "opinions" raised by the respondees ref live feed to/from the switch and the cut wire potentially being a neutral, seem a good point for the OP to start his investigation from (if thats what he intends to do!). You would hope the installer didnt run two 'live' feeds to the switch and realising he only needed one just cut the other and left it ...

 

[MDJ]

Sounds like poorly done 2 plate. Nowt wrong with 2 plate wiring, not the way I'd do it but never mind.
Whte T&E sounds like LSF. Shudder, horrible stuff.

Trev 15-20 years ago white twin and earth was not LSF it was Wicke's own make and redily available off the shelf, I have seen loads of it used, the white cable with red and black cores would be just pvc/pvc, the LSF we know today was confirmed as white and pvc/pvc confirmed as grey when harmonisation occured a few years back, It is my view the white cable in the switches is just cheap twin and earth.

 

[plugsandsparks]

Just come back from a PIR job for a shed and needed to source perm L, N and switched live to a light. Went to the light switch for the perm live and found someone had run T&E to switched cleverly stripped the sheath and cut the red wire, leaving the earth and black wire intact. Black wire was just folded over in switch. earth wire pushed into earth terminal. Go away 7 day message

 

[7029 dave]

Sounds to me, that only the red core in each t&e only being used perm/ s/line, expensive way of doing it!! must be an industrial spark thinking he's still wiring conduit method. lol

 

[trev]

Trev 15-20 years ago white twin and earth was not LSF it was Wicke's own make and redily available off the shelf, I have seen loads of it used, the white cable with red and black cores would be just pvc/pvc, the LSF we know today was confirmed as white and pvc/pvc confirmed as grey when harmonisation occured a few years back, It is my view the white cable in the switches is just cheap twin and earth.

Believe it or not, I managed to avoid all LSF until about 12 years ago. No idea how I dodged it but I did and I'm very sad that I'm being forced to use it now.
The stupid thing about where I'm working is that the communal areas are all LSF "To cut down on hazards should there be a fire" However, the flats that the coffin dodgers live in are all wired in normal T&E, the old T&E that we're replacing is not being pulled out unless it's blocking access to somewhere we need to pull an LSF in.