neutral fault ??

[coxy84]

been asked to look at a light in office unit that was diconnected buy another electricain 2 years ago, the lighting circuit is switch fed with the switch lines running though metal trunking (ceiling mounted) and in singles, the light is a end of line and had been disconnected at the light fitting before it.
between disconnected light and still connected light is an emergency light non maintained which has also been disconnected (neutral only).

the switch line for the lights are interconected loop in loop out and the the em light has a seperate line conductor.

they have a shared earth and neutral looped in and out.

with cables from working light fitting still diconnected i got a voltage of 230v between live and earth and neutral and earth at the non working fitting and at the em light.

but at the working fitting i get 230v live to neutral and live to earth and 0v between neutral and earth, there is no joins or damage to the cables between fittings.

i didnt get any shock off the metal fitting that has been disconnected so it cant really be live can it? but surely its to high to be a inductive voltage?

could it be something to do with the borrowed earths and neutrals?

 

[pushrod]

been asked to look at a light in office unit that was diconnected buy another electricain 2 years ago, the lighting circuit is switch fed with the switch lines running though metal trunking (ceiling mounted) and in singles, the light is a end of line and had been disconnected at the light fitting before it.
between disconnected light and still connected light is an emergency light non maintained which has also been disconnected (neutral only).

the switch line for the lights are interconected loop in loop out and the the em light has a seperate line conductor.

they have a shared earth and neutral looped in and out.

with cables from working light fitting still diconnected i got a voltage of 230v between live and earth and neutral and earth at the non working fitting and at the em light. Sounds like there is a feed from somewhere else. Is the neutral a switch live?

but at the working fitting i get 230v live to neutral and live to earth and 0v between neutral and earth, there is no joins or damage to the cables between fittings. Which is what you would expect

i didnt get any shock off the metal fitting that has been disconnected so it cant really be live can it? but surely its to high to be a inductive voltage?

could it be something to do with the borrowed earths and neutrals?

Difficult to visualise, but thoughts in red and at least it's bumped back up to the top

 

[SirKit Breaker]

Has the disconnected neutral at the EM light also disconnected the neutral to the non working light? i say this because you say the neutral is looped in and out if the fittings.

I am also a bit concerned about you saying "I didnt get a shock of any of the metal fittings", and my worry is that you may have a missing live conductor in there somewhere which if it doesnt earth and take out the breaker, may well take out you.

I would isolate and have a very good nosey about for any missing cables, how many times have you come across someones cut off cables just stuffed into somewhere convenient to hide them cos they couldnt be bothered to do the job properly.

Cheers........Howard