Pipe leaked in the loft, came through the lighting ceiling rose on a landing light on a two way circuit… Funny stuttering crackling noise when off, light working when it is on… Got a little tingle off the light fitting.

Got the pipe sorted, dried the ceiling for 48 hours.

Now 240v across the supply and the load in the rose when switched on, but 70 v across the load (and 40v in the light fitting) when switched off…

10v I’d expect, but 40-70v?

Will we die?! Is this safe?

When switched off the supply side is floating high for some reason. There must be some level of short between the switched supply and the lighting ring main.

I.e there is a break down in insulation either in the terminal block In the ceiling rose or the switched wire.

Probably.

Remove lamps from the circuit and try again… 😉

Thanks. That’s what I thought,

Damn