two way lighting wireing

[moose man]

Come across some two way lighting problem yesterday whilst replaceing a switch plate on the landing for somebody. the strappers and been done in 2 core and earth and thay had used the earth core which was sleaved with red for the common between the two switches is this the way it used to be done a bit worrying

thanks moose man

 

[ProDave]

No.

This is someone's bodge, either to fit two way wiring without pulling a new cable, or because they just didn't understand.

To put it right you need to pull a new 3 core & earth in place of that 2 core.

 

[moose man]

it looks a bit tight to pull a new cable i was thinking of linking the common at the bottom 2 gang switch

then just use the two cores from L1 L2 two L1 L2 on too the landing 1 gang s/w then take a single double insuated cable from common up to light

 

[steptoe]

Thats how it was done a lot previously, just beware of a 'borrowed' neutral.

 

[meady]

I had a similar problem last week. I was asked to do a simple light fitting change like for like, easy job which I fitted in on my way home. Once I took the fitting down I was left staring at cpc on the switch cable as the switch line :-(. Went to the switch to confirm the find. I tested continuity of the core that wasent used from the switch to the light and it showed there was a break. Went into loft and cut the switch cable where it came up and tested continuity there hoping the break was in the loft. No such luck as there was no beep on my t100. I spent 2 hours removing the old cable and replaced with new. It makes me wonder if it had been like that from the start and the cable was damaged after first fix then the sparks doing the second fix couldent be bothered to replace the damaged cable and used the cpc instead. The flat is only 8 years old too

 

[moose man]

thanks steptoe i keep that in mind when i went to cu the lighting for the whole house was on one mcb

moose man

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it does make you wounder like your self this was supposed to be a 10 miin job

that turns out to be longer when covers are removed

 

[ProDave]

keep that in mind when i went to cu the lighting for the whole house was on one mcb

Recent CU in an old house? perhaps there's already a borrowed neutral problem?

 

[moose man]

its an old type cu 1361 typ with wylex plug in mcbs as ask me for a price to replace it but could open a can of worms

might do some test before i give a price

 

[Evans Electric]

Its quite a common bodge Moosey, last one I found was a room stat fitted by a certain nationwide gas supplier who use blue vans . They'd used the earth as the switch wire (would have been safer as the neutral!!!) .

 

[moose man]

whats the best way to test for a borrowed neutral when only one neutral bar in cu

thanks moose

---------- Post Auto-Merged at 21:13 ---------- Previous post was made at 21:07 ----------

Its quite a common bodge Moosey, last one I found was a room stat fitted by a certain nationwide gas supplier who use blue vans . They'd used the earth as the switch wire (would have been safer as the neutral!!!) .

i managed to get hold of some single double insuated cable today not much around up this area at least i can put it right for them . Just use the two cores like i said in previous post

 

[Zeespark]

Run an IR test between the Lines of the 2 lighting circuits Moose.

AndyGuinness

 

[moose man]

thanks zeespark but i think the lighting as been done on one circuit bt no sure unless i drop cover of the cu as one mcb for lighting un less its been double up

 

[ADS]

No 'borrowed' neutral if only one lighting circuit - unless they've 'borrowed' it from the 'Ring Final'

 

[Badger]

Its quite a common bodge Moosey, last one I found was a room stat fitted by a certain nationwide gas supplier who use blue vans . They'd used the earth as the switch wire (would have been safer as the neutral!!!) .

thats like the supply i installed for a new boiler in a refurb, i went back after new boiler installed and theyd ran flex to time clock, room stat pump, and control centre, not a very pro looking install at all,!!

 

[batty]

Plumbers always use flex its the way they do it.

 

[andy_spark]

thanks steptoe i keep that in mind when i went to cu the lighting for the whole house was on one mcb moose man

---------- Post Auto-Merged at 09:25 ---------- Previous post was made at 09:21 ----------

it does make you wounder like your self this was supposed to be a 10 miin job

that turns out to be longer when covers are removed

I wouldn't worry too much about having only 1 lighting cct in a CU. I do a lot of CU changes in council flats and houses and quite often there is a shared neutral or it was only wired with 1 circuit. It's not ideal and probably doesn't fully offer a minimum of nuisance tripping but put the lights on a rcbo and at least nothing else will make them trip. The answer would be to rewire the offending circuit but in my case I'm not paid for that just for a board change. A private job would be slightly different however.

There is never anything as simple as a 10 minute job I always try to cover myself for this sort of thing as you can end up chasing around for ages without making any money if you're not careful. If you are intending to change a CU then insist on a PIR or at minimum some basic testing (IRs, ring end - end & Zs) and a visual investigation into the state of the installation. Offer a price for the inspection which will be discounted to the customer on completion of required work, if not just get paid for the inspection at least your not out of pocket. After all it's their problem and faults, not yours.