In article ,
Duncan Di Saudelli wrote:
Measuring a current flow to ground from this "dodgy" earth, I see a
couple of hundred microamps flowing (actually about 275uA). Not enough
to hurt but you can just about feel a "buzz" on your finger tip.

I shall start trying to trace the lighting ring main back, but I am
puzzled as to why this lighting ring earth should float when a nearby
socket ring main earth doesn't. I am yet to carry out furthr
investigations i.e. other looking at other ring circuits.

For a start, lighting circuits ain't rings - they are radials.

How old is the house? Earths haven't always been required on lighting
circuits. Even although TW&E may have been used to wire them.

Most likely cause is it either isn't connected or is broken somewhere.
Especially where a ceiling rose has been replaced with an alternative
fitting which doesn't have the required terminals.

--
*Give me ambiguity or give me something else.

Dave Plowman London SW
To e-mail, change noise into sound.