Odd wiring and new light and switch.

[DBUK]

I'm hoping someone can give me a few hints here.

I'm trying to install a new bathroom light and pull switch having gutted the bathroom and knocked it though to the previously separate loo. Both room had a seperate light and pull switch. Having removed the old wiring and light fitings I am now left with two cables. One is a live feed + earth, the other is a neutral feed plus earth. They are related in anyway. This doesn't match anything I've seen in any DIY or electrical hand books.

The problem is I cant figure out how these two should be hooked up to the new light fitting ( three way connector ) and the pull switch. The best I can come up with is to wire the live feed + earth to one side of the switch, wire the neutral + earth to the light fitting and the run a feed between the remaining connection on the switch to the live connection on the light.

The question is, and I know you cant make definitive answers based on a forum posting, is this a safe / correct way of doing it?

Thanks

Dave.

 

[fubar]

Sounds like you have lost some cables somewhere. Take a look in the "For reference" section of this forum for a wiring diagram that shows what you should have - hopefully you can work out what to replace from that.

--
Michael

 

[DBUK]

I've checked the referance pages and they match what I expected to see. There are no cables missing that I can find. The previous wiring was in the loft above the bathroom and I have cleared all the insulation etc checking for other wires I might have missed. I'm starting to think it was a bodged job in the first place. The Live + earth appears to come from the landing light fitting, the neutral plus earth from one in a bedroom. All the other lights are still working correctly despite these two cables not being connected to anything else.

 

[breezer]

some times its quicker/ easier to remove wrong wiring and do it properly

 

[plugwash]

what is this cable like?

twin and earth with a core cut back?

a single core and earth in sheath?

seperate cores with only single insulation

i can't see any problem with what you initially proposed provided the live and neutral cores are double insulated

if they are not double insulated then i would remove those wires and take a new spur of twin and earth from an existing light

as for teh cable between the switch and the light the ideal cable would be single core and earth

unfortunately single core and earth is a fairly rare cable type maplin used to sell it but have stopped perelli make it see http://www.pirelli.co.uk/en_GB/cables_systems/energy/catalogue_pdf/lv_pdf/6242y_6242yh.pdf
but i dunno of anywhere that sells it

if you can't get any then just use twin and earth with the black core safely sealed off or better sleeved green/yellow and connected to earth

 

[securespark]

Any chance of some piccys?

 

[DBUK]

Dont have a digital camera, or even a camera phone ( thats a whole different discussion

The live and neutral feeds are both single core + earth sheathed together ( double insulated? ).

I went ahead and connected it up using chocolate block as I originally described and it all seems to work ok. The circuit runs off of a dedicated RCB in the consumer unit. I'm assuming that if that hasnt tripped there is nothing hugely wrong.

I've disconnected it again for now untill I can get some proper cable connectors as the connections themselves will be buried under the loft insulation when it goes back down.

Thanks for the help and advice!

Dave.

 

[ban-all-sheds]

I've disconnected it again for now untill I can get some proper cable connectors as the connections themselves will be buried under the loft insulation when it goes back down.

I hope that if the cables have also been buried under the insulation that proper allowance was made for that when selecting their size and the rating of the protective device.....

 

[Damocles]

So whats the current rating of 1mm in insulation?

 

[ban-all-sheds]

8A.

And if you'd like to also allow for the fact that on a hot day the temperature inside an insulated loft can easily reach 40°, 7A.

So OK - you got me - I hadn't done the sums - it'd be OK on a 6A breaker, which is usually used for lighting.