On Wed, 28 Feb 2007 18:06:53 GMT someone who may be "Innumerical"
wrote this:-

You should run an extra earth wire outside the cable and connect that to the
box also.

Why?

The armour of SWA cable is perfectly adequate as a protective
conductor, if terminated properly and then looked after. The
energised conductors are connected via a terminal strip as is the
protective conductor. The metal box should also be properly
connected to the protective conductor.

Should one wish to run the protective conductor inside the armour
and some more insulation this can be done using a three core cable.
However, the armour and box must be connected to the protective
conductor too.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54