Categories Home improvement

MCBs, MCCBs, And RCCBs: What They Are And How They Work

In every electrical system, circuit breakers are a necessary component. They protect circuits from overcurrents & short circuits, preventing damage to equipment and potential fire hazards. Different circuit breakers are available, including MCBs, MCCB, and RCCBs.

Let us understand what these circuit breakers are and how they work.

What Are Mcbs (Miniature Circuit Breakers)?

MCBs, known as miniature circuit breakers, are automatically operated electrical switches. They are widely used in residential and commercial buildings to protect electrical circuits that may get damaged due to excess current. 

They have a fixed trip setting, and you can easily install them on the distribution boards due to their compact size. With the selected trip setting, they automatically trip during an overload or short circuit. It makes an MCB suitable for protecting electrical circuits against electrical faults or equipment failures. 

You can choose from different MCB types based on their tripping characteristics, breaking capacity, and the number of poles or trappable switches inside the MCB housing. 

What Are Mccb (Moulded Case Circuit Breakers)?

MCCB, or Moulded Case Circuit Breakers, are safety devices used in industrial and commercial applications to protect the electrical circuit from overload or short circuits. They can handle higher currents than MCBs and are therefore used to protect larger electrical systems than MCBs from any damage. 

They have adjustable trip settings and can be used to protect against overloads, short circuits, and ground faults. They are incorporated into the distribution panel and offer a clear signal to users that the power is off.  As they can handle high currents, they are used in various applications, especially on expensive equipment. 

The main components of MCCBs are:

  • Moulding case
  • Terminals
  • Operating apparatus
  • Trip ‘Unit

  • Arc chamber

They are commonly used in industry-level machinery such as welding machinery, motors, generators, electric feeders, capacitor banks, and modifiable trip modes.

What Are Rccbs (Residual Current Circuit Breakers)?

RCCBs, or residual current circuit breakers, are current-sensing devices that protect against electrical shock caused by the current leakage. The device can sense the current flowing through the live & neutral conductors and differentiate between them. 

If the difference exceeds the RCCB’s rated sensitivity, the device will trip and cut off the power supply. They identify and stop current imbalances caused by faults like insulation failures or ground faults in a circuit.

There are two types of RCCBs: the 2-pole RCCB & the 4-pole RCCB.

How Do Mcbs, Mccb, And Rccbs Work?

All three circuit breakers work by interrupting the flow of electricity in a circuit when an abnormal condition is detected. MCBs and MCCBs operate based on the principle of thermal-magnetic tripping, and RCCBs, on the other hand, are based on the principle of residual current tripping.


All three circuit breakers are crucial components of any electrical system and essential to ensuring the safety of people & equipment connected to the system. 

Check out IndoAsian for a wide range of electrical products such as MCBs, MCCBs, RCCBs, and other accessories.