Definition
The switching electrically oper-
ated equipment normal service is
referred functional switching.
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.
Definition
Earthing the connection the
exposed conductive parts an
electrical installation the main
protective earthing terminal the
installation.
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. 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. fuse
or MCB would meet this requirement.
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.
A switch may provide the means isolation, but isolator differs from a
switch that intended opened when the circuit concerned not
carrying current. (IEE Regulation 131.1). The switch-
ing electrically operated equipment normal service referred as
functional switching.
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.
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.
Let now define some the important new words they apply elec-
trical installations. This bonding linking together the exposed metal parts of
an installation known ‘protective equipotential bonding’ and gives
protection against electric shock.
Definition
Bonding the linking together the
exposed extraneous metal parts of
an electrical installation for the pur-
pose safety. addition, means of
switching off for maintenance emergency switching must provided. One
device may provide both isolation and switching provided that the charac-
teristics the device meet the Regulations for both functions.
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. Figure
6.1.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. fuse or
MCB would meet this requirement.
Earthing the connection the exposed conductive parts electrical
installation the main protective earthing terminal the installation. 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. For current flow there must difference potential between
two points, but the points are joined together there can potential
difference.
. Its purpose ensure the safety those working the
circuit making dead those parts which are live normal service.6 shows the connections and equipment domestic service position.
Bonding the linking together the exposed extraneous metal parts of
an electrical installation for the purpose safety
