Let now define some the important new words they apply elec-
trical installations.
Definition
Earthing the connection the
exposed conductive parts an
electrical installation the main
protective earthing terminal the
installation. For current flow there must difference potential between
two points, but the points are joined together there can potential
difference. This bonding linking together the exposed metal parts of
an installation known ‘protective equipotential bonding’ and gives
protection against electric shock.
Earthing the connection the exposed conductive parts electrical
installation the main protective earthing terminal the installation. fuse
or MCB would meet this requirement. These
requirements are met good workmanship carried out competent per-
sons and the installation approved British Standard materials such as
switches, isolators, fuses circuit breakers.
Circuits are controlled switchgear which assembled that the circuit
may operated safely under normal conditions, isolated automatically
under fault conditions, isolated manually for safe maintenance. The switch-
ing electrically operated equipment normal service referred as
functional switching.
Definition
An isolator mechanical device
which operated manually and is
provided that the whole the
installation, one circuit one piece
of equipment may cut off from the
live supply.
Bonding the linking together the exposed extraneous metal parts of
an electrical installation for the purpose safety.
Definition
The switching electrically oper-
ated equipment normal service is
referred functional switching. addition, means of
switching off for maintenance emergency switching must provided.
An isolator mechanical device which operated manually and is
provided that the whole the installation, one circuit one piece of
equipment may cut off from the live supply. (IEE Regulation 131.6 shows the connections and equipment domestic service position. One
device may provide both isolation and switching provided that the charac-
teristics the device meet the Regulations for both functions. fuse or
MCB would meet this requirement. The
equipment belonging the supply authority sealed prevent unauthor-
ized entry, because connection were made the supply before the meter,
the energy used the consumer would not recorded the meter.
Definition
Bonding the linking together the
exposed extraneous metal parts of
an electrical installation for the pur-
pose safety.
To provide overcurrent protection necessary provide device which
will disconnect the supply automatically before the overload current can
cause rise temperature which would damage the installation. Figure
6.
.
Definition
To provide overcurrent protection is
necessary provide device which
will disconnect the supply automati-
cally before the overload current can
cause rise temperature which
would damage the installation.1).1.Basic electrical circuits and cables
131
enclosures, earthing and bonding metal work and providing fuses cir-
cuit breakers that the supply automatically disconnected under fault
conditions.
A switch may provide the means isolation, but isolator differs from a
switch that intended opened when the circuit concerned not
carrying current.
Protective electrical bonding earth
The purpose the bonding regulations keep all the exposed metal-
work installation the same earth potential the metalwork the
electrical installation, that currents can flow and cause electric
shock. Its purpose ensure the safety those working the
circuit making dead those parts which are live normal service
