removing borrowed neutral on landing light

[wilgartw]

i have (had) a borrowed neutral, and some crazy wiring in my lighting circuit, most of which i have put right.

I have two two way switched top and bottom of the stairs, with the live feed going to the bottom switch, and the 2 ways running between them. however which is the most usual:

1. the live feed then goes back down to the floor, and then the live and neutral go up together to the landing light
-- or --
2. the live feed goes from upstairs switch to the landing light, then a separate cable goes from landing to attic. if so do i just run standard 1.5mm and ignore the live?

thanks.

 

[EFLImpudence]

I'm not quite sure of your description.

The object is to have both live and neutral from the same circuit.
It doesn't matter which way you do it.

Either you have to get a neutral to the downstairs switch or
a live to the upstairs switch.

The problem usually is that, wired as it is, you only have TWO strippers between the switches but you need THREE.


1mm² is heaps more than needed for lighting circuits.
Can we get rid of this obsession for 1.5mm², please.

 

[ericmark]

Two way lighting will normally have a three core and earth cable between the switches. The switch with two cables is the master and the neutral to lamp and line feed to master switch should come from the same circuit.

Where there is only two core and earth then it has to borrow a line so the light it borrows from must be on the same circuit. This means often you can't split upper and lower floors.

The upper and lower floors were often split because a standard ceiling rose (which is used as a JB) is rated 6 amp so can't use a larger breaker so cure was to split into two circuits in the main because of quartz lamps. Today there is not really a problem using LED lamps so no reason not to re-combine. Unless it causes a danger due to all lights failing together should a RCD trip.

Although officially a ceiling rose is 5 or 6 amp in real terms there is not a problem with 10A. Where the problem lies is with 10A as a bulb blows specially with type C it can draw so much current it welds to the bulb holder. In theroy there should be a fuse built into every bulb in practice often not there and the MCB will trip with ionisation of the gases in a bulb.

I also can't follow what you are trying to do, so just general information.

 

[JohnW2]

Where there is only two core and earth then it has to borrow a line so the light it borrows from must be on the same circuit.

I suspect that terminology might confuse some readers. AIUI, a load (e.g. a light) is conventionally regarded as being on whatever circuit its L (line/'live') comes from - so, by definition/convention, the L always comes from the 'correct' circuit. Hence, if something is 'borrowed' from another circuit, it is the neutral. That is, I presume, why we hear about 'borrowed neutrals' but not 'borrowed lives/lines'.

Kind Regards, John

 

[EFLImpudence]

I suspect that terminology might confuse some readers.

Was it terminology?

AIUI, a load (e.g. a light) is conventionally regarded as being on whatever circuit its L (line/'live') comes from - so, by definition/convention, the L always comes from the 'correct' circuit. Hence, if something is 'borrowed' from another circuit, it is the neutral. That is, I presume, why we hear about 'borrowed neutrals' but not 'borrowed lives/lines'.

Mmmm, that may well be true by definition, but irrelevant in terms of rectifying.

 

[JohnW2]

Was it terminology?

Well, call it what you like, but eric was talking about 'borrowing a line'

Mmmm, that may well be true by definition, but irrelevant in terms of rectifying.

... unless some readers believed it to be saying that one had to rectify the problem by adding a line connection from whatever circuit was providing the neutral for the light. As I presume you are implying, it can obviously be rectified 'either way around'.

Kind Regards, John

 

[securespark]

TWO strippers between the switches but you need THREE.

Three strippers always better than two!

 

[ericmark]

It may be technically borrowing a neutral, but in real terms it is the line which is taken from another circuit. As to cure there are many ways I will list 3.

1) Use three core and earth between switches however to replace is a major job.
2) Use RF switching.
3) Connect both circuits to the same MCB so combining them into one circuit.

As to using a different neutral wire not really an option, as the lamp swaps which neutral it uses according to which of the two combinations are used to switch on the light. (4 in all but two switch light off)

I have actually seen where an electrician found a borrowed line, and instead of combining the two circuits onto one MCB which then means they are the same circuit he swapped the MCB position so they came from the same RCD! OK it stopped it tripping but did not remove the borrowed neutral.

I suppose you could correct the neutral supply by used double pole switches but in real terms it's the line which is corrected not the neutral.

 

[Poolio90]

I have a "borrowed neutral" on the landing light - which I'm not best pleased about, but can live with.
I recently changed the old light fitting and put a new rose in - but now can't seem to get the darned thing to work.

This should work right?

https://1drv.ms/i/s!AvUDx3iwnbuOjtIfTDfaiWAw_FlvRw

Poolio

 

[EFLImpudence]

 

[winston1]

What does "ring" mean on your diagram? Lights should NOT be on a ring final.

 

[securespark]

Did anybody hear anything then?

 

[securespark]

OP, I would put the landing on the ground floor circuit then it will give some light to the upstairs if that circuit fails.
A bonus of this set up is that the wiring for both switches on the landing feed from the same breaker.

 

[Taylortwocities]

Did anybody hear anything then?

Its all quiet here

 

[deadshort]

Well, call it what you like, but eric was talking about 'borrowing a line'

That explains it ……

DS