Dave Plowman (News) a écrit :
Before about 1970, lighting cable was mostly 3/0.029". Was there an earth
conductor present - and more to the point is it connected at both ends?
There was no requirement for an earth on lighting circuits in those days -
although the cable itself might have had one.

There was, but only usually where flourescent fittings were installed.

Where a normal light was swapped to flourescent, they would run a
separate earth wire - if you were lucky. Many were just installed
without an earth, by bodgers.