"TheScullster" wrote in message
...

"John Rumm" wrote

Or run the cables on the surface: AIUI it's only for cables buried
50mm
the RCD becomes necessary.

Yup, also true.

--
Can't you simply earth the conduit at the point that it enters each back
box by linking to the socket earth?
In this way you cover the vertical drop that is likely to be drilled
through and continuity of these to the horizontal under-floor runs is not
an issue.

Its the old timers.. he is thinking off how they actually ran the protective
earth using the conduit.
I agree that if the protective earth is in that cable earthing the conduit
at either end should comply.
Its no different to SWA which only (in some cases must) be earthed at one
end.