Richard Harrison wrote:

My electric company, the former Houston Lighting and Power Company,
writes:
"All services shall be properly grounded. Note - NEC requires grounding
to a "metallic underground water piping system" if available. Acceptable
alternatives include a driven ground rod which is preferred by HL&P Co.
regardless of the type grounding electrode used. NEC requires that the
"interior cold water pipimg system" be bonded to it."

That last point is the same in the UK. Gas and water supplies are never
relied on to provide an electrical ground, but they must be bonded to
the electrical supply ground.

Additional local bonding is also required for all metalwork in bathrooms
and shower rooms.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek