Difference Between MCB And MCCB

Miniature Circuit Breakers (MCB) and Moulded Case Circuit Breakers (MCCB), are the two main types of circuit breakers used in electrical distribution systems. Both MCB and MCCB are electrical protection devices that are used to prevent damage to electrical equipment and appliances from overcurrents, short circuits, and other electrical faults. 

Since the early 20th century, circuit breakers have been used widely as a safety measure to prevent the overloading of electrical systems. With the advancement of technology increment circuit breakers have evolved and advanced, which is giving rise to the development of MCBs and MCCBs. 

Definition of MCB

An MCB is a type of circuit breaker that is used for low-voltage electrical systems, typically up to 1000V. It is a compact and relatively inexpensive device that is designed to trip or switch off the power when a fault is detected in the circuit. MCBs can be in different current ratings, ranging from a few amps to 125A, and are mainly used for residential and commercial applications.

 

Working

The working principle of the miniature circuit is very simple. Their main function is to protect the equipment from passing overcurrent. It has two contacts one is movable, and the other one is fixed. When the current increases from the predefined limit, their movable contacts are disconnected from the fixed contacts which makes the circuit open and disconnects them from the main supply.

Examples

1. MCBs are commonly used in residential and commercial applications to protect electrical appliances and devices like air conditioners, refrigerators, and computers.
2. MCBs are also used in electrical distribution boards to protect lighting circuits, socket circuits, and other low-power electrical loads.
3. MCBs are used in renewable energy systems like solar PV systems to protect the DC circuits from overcurrents and short circuits.

Definition of MCCB

MCCBs are designed for higher voltage systems, typically ranging from 1000V to 6000V. They are larger and more expensive than MCBs but can handle much higher currents and are more robust in their construction. MCCBs also have additional features like adjustable trip settings, short circuit protection, and thermal overload protection. They are mainly used for industrial and commercial applications where the electrical loads are much higher.

 

Working

The MCCB is basically having two arrangements. One for the over temperature and the other for the over current. It consists of bimetallic contact which expands and contracts when the temperature of the MCCB changes. During normal operating conditions, the contract allows the current to flow through the circuit. But as the current rises beyond the predefined value, then their contacts will warm and expand until the contacts are open. Thus, disconnecting the circuit from the main supply and protects the equipment from damage.

Examples

1. MCCBs are commonly used in industrial applications like manufacturing plants, power plants, and refineries to protect electrical equipment like motors, transformers, and generators.
2. MCCBs are used in electrical distribution systems to protect high-power circuits like switchgear and substation equipment.
3. MCCBs are also used in commercial buildings like shopping malls and hospitals to protect electrical systems from overloads and short circuits.

Difference Between MCB And MCCB

Conclusion

In conclusion, both MCBs and MCCBs are essential components in any electrical system, and their selection depends on the specific requirements of the application. MCBs are more suitable for low-voltage applications like homes and offices, while MCCBs are ideal for industrial and commercial applications with high electrical loads. When choosing between the two, it’s important to consider factors like current rating, trip characteristics, and durability to ensure that the circuit breaker provides the necessary protection for the electrical equipment and appliances.

FAQs on MCB and MCCB:

Q1. Explain the term MCB.

Ans: An MCB is a type of circuit breaker that is used for low-voltage electrical systems, typically up to 1000V.

Q2. Explain the term MCCB.

Ans: MCCBs (Molded Case Circuit Breakers) are designed for higher voltage systems, typically ranging from 1000V to 6000V.

Q3. Write the types of MCCBs.

Ans: The six different types of MCBs are A, B, C, D, K, and Z.

Q4. How MCBs and MCCBs are different?

Ans: The difference between these is their working capacity such that MCBs are having just 125A but the MCCBs are having a current rating of up to 1600 A.