wiring colours

[lynne87]

Hi

I am installing some new lights in my flat and and am unsure which mains wire is live and which is neutral.

The colours are black, yellow and green and the flat was built in the 70s. I am happy that green is earth but am unsure about live and neutral.

I can't just follow the wiring for the old lights as it turns out some were connected brown (light fitting) to black (mains) and blue (ligtht fitting) to yellow (mains), and others the opposite way around.

Help!

 

[SUNRAY]

Hi

I am installing some new lights in my flat and and am unsure which mains wire is live and which is neutral.

The colours are black, yellow and green and the flat was built in the 70s. I am happy that green is earth but am unsure about live and neutral.

I can't just follow the wiring for the old lights as it turns out some were connected brown (light fitting) to black (mains) and blue (ligtht fitting) to yellow (mains), and others the opposite way around.

Help!

First of all welcome Lynne.
I think a guess can be made about his but more detail, especially good pictures of the various locations needed please.

 

[omega015]

Before disconnecting anything make sure you take pictures, noting where wires go to and even putting some identification on each cable (like numbers, letters, dots, masking tape, etc...). But yes if you can upload some pictures it would help us give you some safer advice.

 

[ban-all-sheds]

The colours are black, yellow and green

Yellow?

Really?

 

[securespark]

Why not?

 

[Taylortwocities]

To know for sure, you need one of these

and one of these

or one of these

 

[John D v2.0]

Multimeter is fine, just disconnect at the cu and measure from there.
Not sure how that comes regarding all conductors being identified at their terminations though, it should be either new, old, or sleeved colours.

 

[Taylortwocities]

You make it sound so easy…

 

[sparkwright]

Seems obvious to me.

A 70s block of flats.

Conduit.

Singles.

Red used as permanent live.
Black used as neutral.

Yellow used as switch live.

Only switch live and neutral required at light fitting (tho reds probably looped straight through ceiling pot box.

Easy way to confirm all of the above is to look behind a light switch, where I would expect to see yellow and red wires.

 

[mwatsonxx]

Seems obvious to me.

A 70s block of flats.

Conduit.

Singles.

Red used as permanent live.
Black used as neutral.

Yellow used as switch live.

Only switch live and neutral required at light fitting (tho reds probably looped straight through ceiling pot box.

Easy way to confirm all of the above is to look behind a light switch, where I would expect to see yellow and red wires.

ureavinalarf, a flat wired in conduit and singles perhaps if it was 40's or 50's, in the 70's it would have been piro/micc.

 

[stillp]

in the 70's it would have been piro/micc

Not in any that I've seen.

 

[333rocky333]

There is some council blocks in east London that have Pyro flushed in the walls, I think a it was a phase they went through in case someone nailed into the wall, though a majority I have seen have been loop in conduit.
It is a remote possibility its 3 black pyro cores marked with Green and Yellow phase tape I suppose.

 

[Taylortwocities]

Pictures please!

 

[securespark]

in the 70's it would have been piro/micc.

I have seen more 70's flats with conduit that I have MICC. Octoflex or Aercon were used too.

As for the 40's and 50's, Octopus was often used, with a huge central JB for lighting.

 

[deadshort]

Not in any that I've seen.

Yellow =sw live
Why would yellow be neutral if there is a black ?

DS