A ground is a direct electrical connection to
the earth, a connection to a particular point in
an electrical or electronic circuit, or an
indirect connection that operates as the result
of capacitance between wireless equipment
and the earth or a large mass of conductive
For all practical purposes the earth potential is taken
The Neutral wire in an A.C supply & middle wire in
three wire distribution D.C supply are always
The earthing of electrical equipments brings the
equipments to zero potential & avoids shock to the
operator, under any fault conditions
In any grounded supply system where neutral is not
earthed ,under a single earth fault anywhere in the
system, the voltage of two healthy phases with
respect to the ground increases to three times to the
normal phase voltage.
Such an over voltage is harmful to the various
electrical equipments .
Hence all modern supply systems use grounded
In India three phase ,four wire distribution is
The potential between any two phases (line voltages)
is 400 while between any one of the three phases &
the neutral is 230.
The single phase equipments are supplied with one
phase called line & a neutral.
The neutral wire is always grounded at generating
The grounded neutral supply system has
It is very easy for earth protection.
Spikes of over voltages are easily dissipated
Less stresses on insulation ,if there is earth