wrote in message
ups.com...
mac wrote:
What is the legal position regarding earthing arrangements for a
(domestic)
property that has as its main earth, a connection to the income cold
*water*
pipe. I know that this is not allowed by the regs (although I think it
used to
be?). There are several houses I know of in this suburb area that have
this as
the only earth. Does the use of an RCB on the CU make this acceptable or
*must*
it be changed?. If it has to be changed, what to? I don't know if PME is
available here - if not how about earthing rods per propery? Although
safety
comes first of course I guess this could start to get expensive
especially in
that each such arrangement has to be retested/certfied by some
organisation?


there are proably milions of propertes like this. As long a your water
supply remains metal, its normally a non issue. Metal water pipes make
excellant earths. However if the pipe upto the house is ever replaced
with plastic, you've got a real problem, and the installation could
become dangerous in some cases.

Simplest solution if youve got plastic water pipe is to add an earth
rod and connect it to the existing earth - dont undo whats there. Note
that if relying on an earth rod, RCD or ELCB protection will be needed.


NT


The argument against relying upon a service for an earth is that the
material used can be changed on a whim by the service company at any time
and is not under your control.