Yellow Conductor Outside Light

[dmh]

Good morning one and all.

I was asked to look at a faulty outside light at the weekend and soon resolved the problem and got it working but I was puzzled as I had an extra conductor (a yellow one). Testing it suggests that it was a live conductor with 240v between it and neutral. There was no wiring diagram / label so coundn't work out what this extra conductor was (it was wired to to a separate terminal point, not connected with the other conductors). A second light a few yards away had the normal live, neutral, cpc conductors.

Anyone able to advise what this extra live conductor is doing for future referance?

 

[nickblake]

it is possible that it was a permernant live or a switched live was the cable a 3 core red blue yellow , what is done some times is to install a 3 core and earth to outside lights the permernant feed to operate a Pir controlled light this would also providing a switched live to overide the PIR

 

[dmh]

Thanks Nick, it was exactly that.