Voltage between L and N

Upon changing an emergency led and isolated on the key switch.

On confirming dead I seem to have voltage between N E.

Any advice would be appreciated I can call an electrician but wish to know why

 

My questions are shouldn't the emergency light be completely isolated on the key switch. Or is it safer to hit the breaker!

I know this fault will have to be found. Would it be a case of testing polarity as I do have a polarity tester for lights.

 

First of all I used a fluke voltage pen which showed voltage then I thought I'd be certain so tested with the the proper digi lock voltage and continuity tester

 

Yes they are non maintained

 

Not sure quite what you mean John, key switch isolates power light comes on.

No voltsge should be present unless from battery. So I'm guessing there is a fault polarity. Or a reasonable explanation

 

I had 240 present,

I have a multi meter,

 

I will check Tommorrow.

Shouldn't I have zero voltage across all.

Is it safe to change as there is no power on the Line conductor. Is that what you mean

 

I'm using the DL6780 Voltage & Continuity Tester

With one probe on the L and Other probe on N zero voltage.

Same method I'm picking up 240 on N -E

 

This is to clarify if it is the Earth or the Neutral?

 

I'll check Tommorrow but I'm pretty sure it is Just N - E

Which is strange.

Am i right in thinking to change the light the MCB would isolate it all.

Maybe back feeding off the neutral?

 

Thankyou Nigel!

So these key switches just cut the L for testing. I'll use the Lighting MCB in the DB. I was thinking along those lines.

So that is perfectly fine. What I mean is im picking up the Neutral voltage as the key switch isn't double pole.