Leakage current detector (RCCB)

The Fault current overloads and short circuits
can be detected by circuit breakers like MCB’s
MCCB’s & HRC Fuses etc. But, Circuit
breakers don’t detect leakage currents, which
are dangerous for humans and livestock and if
not detected can lead to fire hazards. We need
a solution that detects such leakages currents
and disconnects the circuits from the power
supply. Here comes the solution in the form of
RCCB (Residual Current Circuit Breaker) also
known as ELCB (Earth Leakage Circuit
Breaker) which provides protection against
direct and indirect contact of personnel or
livestock and against probable fires.
RCCB works on the principle that in an electrical circuit the incoming current is the same as out
going current as shown in the Diagram. RCCB incorporates a core balance transformer having
primary and secondary windings and a sensitive relay for instantaneous detection of fault signal.
The primary winding lies in series with the supply mains and load. Secondary winding is
Connected to a very sensitive relay. In a faultless situation, the magnetizing effects of the current
carrying conductors cancel each other out. There is no residual magnetic field that could Induce a
voltage in the secondary. During flow of leakage current in the circuit an imbalance is created in
the circuit which gives Rise to leakage flux in the core. This leakage flux generates an electrical
signal that is sensed by the relay and it trips the Mechanism thereby disconnecting the supply.