HF Lighting hot/loose neutral?!

[riotmaster]

I havent looked further than the fitting but...

An office full of HF modular fittings working fine but one, so I switched off the lights I'm working on, tested for dead ok, but when I pulled the neutrals out, the other half of the room began strobing and the neutrals were sparking off each other. There was 120V between each neutral leg...

Any idea why or how... ANY thoughts would be appreciated.

 

[aptsys]

Borrowed neutral.

 

[Guest123]

When you say switched them off do you mean just the light switch for that room or the MCB for the circuit??

If just the light switch then more than likely other rooms/fittings on that circuit were still switched on and disconnecting the neutrals upstream of these fittings meant the return path disappeared.

 

[riotmaster]

Yeah it was the MCB, worked on it at the weekend, it had been pinched... from a socket(!) Just ran a neutral back to the board, was above a suspended ceiling and the board was in the corner, seems to me it would have been easier than splitting the ring just to get the neutral in the first place. Odd.

 

[aptsys]

I kind of expect borrowed neutrals from other lighting circuits, but to borrow from a socket... ! Copper must have been expensive when it was wired!