Strange readings on lighting circuit

[Bing]

Hi all.

Iv'e got some strange readings on a lighting circuit.

L - N = 240v
L - E = 122V
N - E = 116V
Continuity between N - E the Meter is pulsing without any reading.

I'm assuming that i have some kind of Floating Earth fault, but if so, why do i get 122V between L - E and 116V between N - E. I would expect with a Floating Earth not to see any potential difference at all.

Any advise would be appreciated.

I tried searching the Forum but couldn't find the same kind of fault.

Steve.

 

[davelx]

Capacitive coupling will put a floating earth conductor at about 1/2 supply voltage.

 

[Bing]

Thanks for the reply Davelx.

So 116V between N - E is roughly 1/2 supply Voltage, like you have suggested. What could be causing this Capacitive Coupling?

If i connect the Floating Earth to a good Earth will the problem disappear? or will it trip the RCD on the Consumer Unit.

Steve.

 

[Spark123]

You need to trace the fault to where it has become disconnected and fix it properly.
If the insulation is sound (probably is) then it shouldn't trip an RCD however it is better if it did than to have a floating earth.

 

[Bing]

Thanks for your advice Spark 123. I was trying to think of a quick and easy solution, which didn't involve rolling around in a tiny loft space, but your right, i need to find the disconnection.

Many thanks.

Steve.