11 October 2019

Difference between MCB and RCBO

MCB stands for miniature circuit breaker while RCBO stands for a residual current circuit breaker with overload protection, this both are circuit protection devices. These devices are most commonly used in the distribution board in the office, home, theatre, commercial building, low voltage power distributions, etc.

What is MCB?


MCB is designed to operate on overload current and they can be used as protection devices for the individual circuit. MCB can also provide magnetic fault protection and short circuit protection.

What is RCBO?


As the name suggests the operating fundamental of RCBO is to operate on residual as well as overload current. RCBO is a combination of MCB and RCCB. When in some current imbalance occur the RCCB will operate ad when there is overload in the circuit breaker will operate.

Difference between MCB and RCBO :

  • MCB stands for miniature circuit breaker while RCBO stands for a residual current circuit breaker with overload protection.
  • MCB can provide protection against overcurrent and short circuit only while RCBO can provide protection against overcurrent and earth leakage.
  • MCb can not protect against earth faults while in RCBO can protect against earth fault, electric shocks that MCB may not do.
  • MCB is selected based on the load, the maximum short circuit during overload and short circuit,  RCBO is the combination of MCB and RCCB. It is selected based on the load and maximum short circuit current it ca interrupt, trip curve and maximum leakage current.
  • MCB is used to protect lighting circuits, air conditioners and other home applications RCBO is used for protection against electric shocks. Hence it is mainly used to interrupt the power to water heaters, power sockets, etc. 
  • MCB is monitoring the current flow through the line and interrupts the circuit during overload and short circuit, while RCBO is not only monitoring but the current flow through the line interrupt the circuit during overcurrent, short circuit, and earth leakage.