RCBO (Residual Current Circuit Breaker with Over Current Protection) is a type of circuit breaker used to protect the circuit from over current and earth leakage current. In this way RCBO as an electrical appliance combines the functionality of both MCB (for overload/short circuit current protection) and RCCB/ELCB/RCD (earth leakage current protection) and are now becoming very popular in domestic electrical installations. A lot of electrical utilities like BSES & NDPL in Delhi, allocate energy meter connection only when the consumer produces an invoice showing purchase of RCCB/RCBO, implying he has installed these devices for protection.
Earth leakage occurs when there is accidental break in the circuit through poor electrical wiring. Over-current comprises of overload and short circuit. Overload occurs when too many devices are used on the circuit and short circuit occurs when there is direct connection between the live and neutral conductors. These cases become risky for human lives apart from causing damage to the buildings. RCBO has the ability to sense these faults and trip the circuit to ensure protection of the people and other connected appliances.