"Christian McArdle" wrote in message
et...
& the armour is no longer no longer acceptable as an 'earth'
should be an internal conductor or an external (min) 10mm

That's a new one to me. When did it change?

Dunno but our NIC inspectors don't allow it now
and 10 years ago when I ran an Amusement Park
we had to run separate protective conductors.

Also when I did multistory bedsit conversions
sep earth was required.

Used to be common to use bonding clamps
on cut back armour to export an earth