What is MCCB (Molded Case Circuit Breaker)? Function, Application

An MCCB or Molded Case Circuit Breaker is an electrical protective device that gives protection against overload fault and short circuit fault. It is a very important electrical protective device that comes after the MCB. The full form of MCCB is Molded Case Circuit Breaker. It gives the protection against short circuit fault, overload, or over current fault like an MCB but it has some additional features. MCB is used in low voltage and low current electrical circuits and it is available up to 125A current rating. On the other hand, the MCCB is available in medium to very high current ratings (up to several thousand amperes). MCCB is mostly used in industrial applications, it is not so much used for domestic purposes. It is used for electrical protection purposes along with the switching of power supply. You can see the incoming breaker of any medium voltage switchgear panel is an MCCB.

MCCB Function

The main functions of an MCCB are,

1. Overload or overcurrent protection
2. Short Circuit Protection
3. Switching of electrical power supply

When the topic comes about electrical protection, the overload fault, and short circuit fault are very common. In fact, these are must considerable for any electrical circuit from low voltage to high voltage. Both of these can create very harmful effects and damage to the electrical circuits, systems, devices. In the older days, electrical fuses are used for these protections. But there were so many hesitations and difficulties because of the replacement of the fuse element after every fault. After that MCB came and replaced the fuse. But the MCB also gives protection up to certain amperes. So, for the high current circuit, we need an advanced device. MCCB provides this function.

The additional features of the MCCB are,

1. Adjustable tripping current setting function
2. External indication and controlling function
3. More sensitivity
4. High voltage and High Current Capacity than MCBs.

Difference between MCB and MCCB

We can also say, these are the common Advantages of MCCB over MCB.

1. MCB stands for Miniature Circuit Breaker whereas MCCB stands for Molded Case Circuit Breaker.

2. MCB can be used up to several amperes(up to 125A) whereas the MCCB can be used up to several thousand or kilo amperes(up to 2500A).

3. The interrupting current rating of the MCB falls under 10KA whereas the interrupting current rating ranges from 10KA to 85KA.

4. There is no adjustable tripping current function in the MCB but the MCCB has an adjustable tripping current function. Where we can set the trip current at which the MCCB will Trip.

5. MCB can be used for low breaking capacity only but the MCCB can be used for medium to high breaking capacity.

6. MCB does not have any function for remote controlling or tripping indication. But the MCCB can be operated remotely and the tripping indication circuit can be connected using the shunt coil.

Use and Applications of MCCB

1. MCCB is used for switching, overload protection, short circuit protection from low voltage low current circuits to high voltage-high current circuits.

2. MCCB is used in the electrical feeder distribution panel as a main incoming breaker.

3. MCCB is used for the protection of high voltage capacitor banks, electrical machinery, Motor Control Center(MCC) Panel.

4. MCCB is used in high current devices, machines as the main switch.

5. MCCBs are used in Three Phase Power Distribution Boards.

Read Also: 

• What is Ground Fault Circuit Interrupter(GFCI)? Use
• [Explained] Motor Circuit Protection System and Devices
• MPCB Uses, Advantages, Connection | Motor Protection Circuit Breaker
• Electrical Transfer Switch Use, Operation, Diagram
• Types of Electrical Panel and Switchgear used in Industry

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