Question on a landing light wiring

[t3rm3y]

I was planning on adding a loft light so bought a junction box, t&e and a switch.
Went in loft. Found the nearby cable from the landing light and cut it. Found the cable only contained one red wire...
Now not sure if can still connect it as planned?
I have retermibated it together in the junction box. But can I connect my live to this from the t&e cable I bought? What do I do with the neutral and earth as nothing to join them too. Is it safe ?

 

[ban-all-sheds]

But can I connect my live to this from the t&e cable I bought?

You can, but unless you also have a neutral your new light won't work.

http://www.google.co.uk/search?q=electrical+circuits+101

Is it safe ?

The earth core should be connected to the lighting circuit earth.

Found the nearby cable from the landing light and cut it. Found the cable only contained one red wire...

What other conductors/cables are there at the light?

Are all the cables for the upstairs lights accessible in the loft?

 

[ericmark]

It is not standard to have a single wire feeding lights. There are a number of standard cables, with either two or three insulated conductors and often a bare earth wire.

To have a single conductor it would seem some one has modified what you have, it was common at one time to use twin and earth between light switches and borrow the line from another circuit, this caused radio interference and also required both lights to be fed from the same overload device.

So when the quartz lamp became popular people needed to split the circuits so now they needed an extra conductor, so to comply people ran in extra wires.

So we have ended up with odd wires where people have tried to upgrade, without any record of what they have done.

There is no easy answer, as we have no idea why a single wire is used, only option is to test and record, and can't do that remotely.

 

[davelx]

It is not standard to have a single wire feeding lights.

It used to be for two-way switching of the landing light from downstairs and upstairs (OP - can you turn your landing light on and off from two different places, eg downstairs hall as well as upstairs?)

It sounds to me as if it's an old house like mine (1930), with a single lighting circuit (so no borrowed neutral issue) with two-way switching to the landing light wired the old way, as follows:

Live feed into Common terminal of landing light switch in the hall downstairs (you'll probably find the incoming live feed looped across from that terminal to one of the terminals of the hall light switch, if it's a dual gang). Two strapper cores in another cable connected to L1 and L2 terminals of the switch running to the L1 and L2 terminals of the upstairs switch. Single core cable running from the Common terminal of the upstairs switch to the light - I would guess that that is the single core cable you have found.

There must, of course, be more than just one conductor connected to the landing light or it won't work, so if you can find the other cable you should find that the neutral of that is connected to the other side of the lamp. It might even have an earth - though not likely if it's the original wiring.

If the above checks out, then you cannot use the cable you have cut to feed the loft light unless you want it to depend on the landing light being switched on. You will have to take the LN&E feed from another of the upstairs lights. in any event you need to find N and E for the new lights, as well as the live feed.

 

[t3rm3y]

Yes it can be switched on downstairs and up. House is only 1970's ish..
There is one other cable coming out of the ceiling rose but this appears to go to bathroom lights which were installed about a year ago. I'm assuming the electron just ran his cable off the light bulb connectors which is why I assumed just cutting it at incoming point and putting a junction box would work.
I have found another light so will use that cable. I assume my thinking is sound-cut one of the existing t&e (hopefully) cables and add a junction box with my new light socket off this? Doesn't matter on the cable I cut this time? Looks like about 3 cables going on to the cileiling rose.

 

[rsgaz]

Run the new cable from an existing ceiling rose. You don't need this extra junction box.

 

[EFLImpudence]

Don't cut any more cables at least until you know what you are doing.

 

[t3rm3y]

Yeah I was just trying to minimise work. Should have been simple-minded cut cable, join cable, add new cable. Instead of taking light out. Go in loft, drop cable, go back down. Join cable, go back up and run cable..
I'll have to revisit this again tomorrow now. Thanks for input davelx

 

[yorkspark]

instead of cutting random cables and hoping for the best, you need to trace a permanent live,neutral and earth
drop the rose from the upstairs lights and test, if no perm live then find the upstairs joint box and test
then take a twin and earth to new attic switch and then a twin and earth to the new light fitting, terminate and test

 

[ban-all-sheds]

.... simple-minded ....

That's the problem. I don't mean you, personally, but your approach, as it is not based on a genuine understanding of how lighting circuits work.

If you'd found a twin & earth cable running to the light, i.e. L/N/E, and connected to that you might now have a loft light that only works when the landing light is on.

Or you might now have a number of lights in the house which don't work unless the loft light is on and are really dim when they do.

As EFLI said, you need to know what you are doing.

• https://www.diynot.com/wiki/Electrics:Lighting
  
  
• http://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners#Lighting
  

Do you have more than one lighting circuit? If you have separate upstairs/downstairs ones then be very careful, as you probably have a borrowed neutral, and that can bite you when working on one of the circuits - turn them both off.

https://www.diynot.com/wiki/Electrics:safety_information:sneutral

 

[t3rm3y]

Hi ban. I did turn both circuits off before snipping, i have now checked the other lights upstairs and all have 3 cables already, loop in, loop out, switch.(apart from landing) I didn't think the connections would fit another cable hence why I was considering the junction box(I remember checking one before and that's why bought the box). Didn't think the landing light would be any different just went for the closest. I'll look for a non switched loop in and see if can jumper on the connectors instead of cutting cables.

 

[Risteard]

In spite of incorrect advice from some it is actually perfectly normal to have PVC/PVC singles or single & Earth on lighting circuits. They are frequently used here even to this day.

It is, however, true that if you are not competent to be working on your electrical installation then you are a danger both to yourself and to everyone else utilising/in proximity to that electrical installation.

 

[ban-all-sheds]

The problem though, Risteard, is that you don't know where "here" is.