Difference Between MCB, MCCB and RCCB

Electricity has become an indispensable, dependable and leading power source for today's humankind. With highly advanced, enhanced, and developed demand for usage and applicability of electricity comes newer and more dangerous hazards. A mere power overloading situation can lead to severe damage to life and property alike. And this brings us to our topic of discussion for the day, that is, a circuit breaker. 

What are Circuit Breakers?

They are switching devices that automatically or manually function to control, regulate, and protect an electrical system. Based on the working mechanism or situation difference, one can categorise circuit breakers as MCB, RCCB, and MCCB.

Difference Between MCB and MCCB, and RCCB

Let's try and comprehend each type of circuit breaker to distinguish them from one another.


A miniature circuit breaker (MCB) is the electromagnetic device that serves as the complete compound in a molded insulating type of material. The primary function of MCB is to open a circuit by breaking the flow of current when excess current, caused due to imperfect design, overload, or short circuit, flows through the device. Like any other switch, an MCB can be turned ON or OFF by the controller.


The Molded Case Circuit Breakers (MCCB) controls electric energy distribution and provides overload and short circuit protection. It is an electromechanical device that guards a circuit from short circuit and over current. Its primary function is to offer a means to manually and automatically open a circuit in different situations. 

Unlike fuses, MCCBs can be reset after a mistake, and they also offer enhanced operator safety and comfort without leading to high operating costs. Commonly, these circuits contain thermal current for over current and the magnetic element for short circuit release to work faster.

Additionally, a molded case circuit breaker also offers overload safety through a temperature-sensitive device. It is mainly a bimetallic connection that gets enlarged at different rates when subjected to a high-temperature value range. Under functional conditions, the bimetallic link permits electric current to flow via MCCB. Whereas when the current value crosses the predetermined tripping voltage, the connection heats up, getting molded because of the thermal rating of heat enlargement inside the connection. And finally, the connection curves over and pushes the tripping bar, unlocking the junction that leads to circuit interruption.


Residual Current Circuit Breaker (RCCB) are essential current sensing devices used to safeguard a low voltage circuit against any faults. They include a switch that turns off the circuit when a fault occurs. RCCB functions to secure people against electrical shocks, fires, and electrocution caused due to wrong wiring or any earth faults, making it very critical in situations where a sudden shock or fault happens in the circuit.

For instance, if you contact an open live wire in an electrical circuit that does not have an RCCB, a ground fault may occur, putting you in a dangerous situation of receiving a shock. Whereas, if a similar circuit is defended with an RCCB, it will break the circuit in a second, protecting you from the electric shock. Therefore, this circuit breaker acts as a must-have device in an electrical circuit.

These protective devices play a significant role in ensuring electrical safety for any electronic system. Therefore, you must make additional efforts to ensure that you employ high-quality devices from companies like Schneider Electric. 


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  1. author
    27 Aug 2019
    Tomas Mandy

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    1. author
      27 Aug 2019
      Britney Millner

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  2. author
    27 Aug 2019
    Simon Downey

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