In message , BigWallop
writes
snip
You should also bond
together all the pipework around the hot and cold water storage tanks.

All the pipes which connect to the central heating
boiler, including the gas connection, should also be bonded together at the
closest point where they meet at the boiler. The boiler itself should
provide an earthing lug if the casing and chassis have exposed metal parts,
which most do.

There is no requirements to festoon yours tanks and boilers with
supplementary bonding.
Supplementary bonding only applies to "locations of increased shock
risk, such as those in Part 6" (471-08-01)



If any plastic pipework or joint fittings are used, then the earth bonding
should by-pass it and be connected to the metalwork where any valves or tap
connections have been made to all appliances, this includes all points on
the water and gas distribution systems.

However, if a generally plastic-plumbed situation, there is no need to
earth bond short sections of copper used as final runs to taps,
radiators etc.



--
Steve