A Quick Guide for Circuit Breaker

A circuit breaker is basically a safety device for any property that uses electricity. These devices play the role of a third party in the complex and dangerous wiring system. MCB, MCCB, RCD, RCCD, RCBO are all circuit breakers. They are used in the home to prevent human hazards and equipment damage.

These appliances are designed to perform specific functions. It is their special features that make them unique. However, the main difference is that MCB, RCDs and RCCB are used for low currents, down to 125 amps. However, MCCB is used for large currents up to 1000 amperes.

1. What are MCB and MCCB?

Most people tend to confuse the difference between MCCB and MCB. Although they are both fusing mechanisms, there are major differences between the two that make them both competent for specific tasks.


MCB is an abbreviation for miniature circuit breakers. MCB is an electromechanical device that automatically cuts off the circuit when an abnormality is detected. Miniature circuit breakers can easily sense overcurrent caused by short circuits. The working principle of this kind of microcircuit is very simple. In addition, it has two contacts; one is fixed and the other is movable.

If the current increases, the movable contacts are disconnected from the fixed contacts, disconnecting the circuit and disconnecting them from the main power source.


Molded-case circuit breakers, however, are abbreviated as MCCBs. Molded case circuit breaker is a protection device that protects the circuit from overloading. In addition, it has a manually operated switch for tripping the circuit. The device has two configurations, one for overcurrent and one for overtemperature. In addition, the molded case circuit breaker is composed of bimetallic contacts, and when the temperature changes, the bimetallic contacts will shrink and expand.

The contacts allow current to flow through the circuit under normal operating conditions. However, when the current exceeds a preset value, their contacts will warm up and expand until the contacts open. Therefore, the circuit is disconnected from the main power supply and the equipment is protected from damage.

2. Similarities between MCB and MCCB

The following are some common features and functions of MCB and MCCB:

  • They all provide a kind of protection
  • MCB and MCCB detect and protect the power circuit to prevent short circuit or over current
  • Mainly used for low-voltage or low-voltage circuits.

3. The difference between MCB and MCCB

MCBs and MCCBs differ mainly in their capacities. On the one hand, the rated current of the miniature circuit breaker is less than 100 amperes, and the interrupting current is less than 18,000 amperes. In addition, their tripping characteristics may not be adjustable because they are mainly used for low circuits.

On the other hand, MCCB provides as low as 10 amps and as high as 2500 amps, depending on needs. Their interrupt frequency is between 10,000 and 200,000 amperes. In addition, the feature of MCCB is that the adjustable stroke element is a more advanced model.

Other differences between MCB and MCCB include;

  • MCB trip circuit is fixed and movable in MCCB.
  • Mcb is less than 100 amperes, while MCCB is as high as 2500 amperes
  • In MCB, remote on/off is impossible, while in MCCB, it can be achieved by using a shunt line
  • MCB is mainly used for low current circuits, MCCB is used for high current circuits
  • MCB is used in low energy consumption areas (home use), while MCCB is used in high energy consumption areas (large industries).

4. What is RCB, RCD, RCCB or RCBO?


RCCB is a residual current circuit breaker. RCCB is also called RCB or RCD. RCD is a residual current device, and RCB is a residual current circuit breaker. The RCCB is an electrical wiring device that will break the circuit once it detects that the current leaks to the ground wire. It can also prevent electric shock or electric shock due to direct contact.

Both RCBO and RCCB are residual current protection devices. This protection is achieved by monitoring the current in the line and neutral. In a normal circuit, the current through the line is equal to the return flow at the neutral point.

However, in an abnormal situation, this return flow may not be equal to the current flow of the line. The residual current device will detect this condition and interrupt the circuit.

Bank branch office

RCBO is the abbreviation of “Overcurrent Residual Current Circuit Breaker”. RCBO combines the functions of MCB and RCD/RCCB. When there is current leakage, the RCBO trips the entire circuit. Therefore, when the circuit is overloaded, the internal magnetic/thermal circuit breaker element will trip the electronic device.

RCD Vs. RCBO: Similarity

These two types of electrical equipment are usually found in fuse boxes, which are often referred to as consumer units or circuit breaker panels. Similarly, they all help protect the system.

5. RCD and RCBO: what is the difference?

RCDs can prevent electric shock, residual current and ground faults. On the other hand, rbos can do what RCDs can do, protecting circuits from short circuits and overloads. rcb is essentially a combination of MCB and RCCB. Therefore, it can protect against overload and short circuit.

The difference between RCD and MCB

MCB cannot prevent ground faults. On the other hand, RCD/RCCB protection circuit to prevent a ground fault

MCB does not completely protect humans from electric shock. However, RCD protects humans from fright.

MCB is available in single-pole, two-pole, three-pole and four-pole. On the other hand, RCD does not have a single-pole option, but there are two-pole, three-pole and four-pole options.

MCB is mainly used in households and industries, while RCD is mainly used in households.

6. Conclusion

Circuit breakers play a vital role in protecting the wiring system and humans from electrical accidents. Some common options include MCB, MCCB, RCCB, and RCBO. However, RCBO is a combination of MCB and RCCB, also known as RCD/RCB.

Chint circuit breaker is one of the first choices to help families and industries prevent electrical accidents. Designed specifically for the global market, these circuit breakers are of top quality and provide maximum functionality. Consult an electrician expert to help you better understand the different types of circuit breakers and the differences between them.


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