MCB : RCCB
RCCB is the safest device to detect and trip against electrical leakage currents, thus ensuring protection against electric shock caused by indirect contacts. These devices must be used in series with an MCB or fuse which protects them from the potentially damaging thermal and dynamic stresses of any over currents. They also act as the main disconnecting switches upstream of any derived MCB (e.g. domestic consumer unit).
MCB : RCBO
RCBO are commonly used in applications where there is the need to combine protection against overcurrents (overload and short-circuit) and protection against earth leakage currents.
RCBO help in sensing this kind of faults and trip the circuit ensuring complete protection of the people and connected equipments.