"David Hansen" wrote in message
...
On Thu, 17 Sep 2009 08:40:14 +0100 someone who may be "nightjar"
cpb@insert my surname here.me.uk wrote this:-

As noted, the earthing it offers
can be unreliable, so I always run earth wires in it as well.

If it is installed and maintained improperly. However, that is true
of other ways of doing the same thing.

For the marginal cost of an extra wire run, it is safer to assume that it
will, at some point, not be properly maintained.

Colin Bignell