Residual Current Circuit Breaker is primarily designed for protection from earth fault and its consequence to human life such as electrical shocks.
As per studies, a person is able to sustain electrical shocks only to the magnitude of 30 mA.
Thus, RCCBs in low voltage protection are designed such a way that they will trip off the circuit even for small change in residual current value of up to 30 mA. The response time is usually within 40 msecond, thus ensuring that the person is fully protected from electrical shocks at all times.
Higher values of 300 mA are used in cases where a protection from fire hazard is sought. This is useful in places where a lot of flammable material is stored.
RCCB is an essential protective device in your electrical circuit that helps to prevent electrical hazards in cases of earth faults. A properly set RCCB will ensure that there is no fatal injury caused to human being in case of an accidental touch to live wires.