The IEE Wiring Regulations Explained and Illustrated, 2nd Edition

Earthing

2 All metalwork liable to introduce a potential including earth

potential, termed extraneous conductive parts. Examples are

gas,

oil and water pipes, structural steelwork, radiators, sinks

and baths.

The

conductors used in such connections

are

called protective

con-

ductors,

and they can be further subdivided into:

1 Circuit protective conductors, for connecting exposed conduct-

ive parts to the main earthing terminal;

2 Main equipotential bonding conductors, for bonding together

main incoming services, structural steelwork etc.; and

3 Supplementary bonding conductors, for bonding together

sinks,

baths, taps, radiators etc. and expose ...