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MCB and MCCBs are common protection devices used in low-voltage electrical distribution systems, but how are they different? This post about MCB vs. MCCB aims to answer that question in more detail. It will compare MCB and MCCB breakers, examining their working and differences. Among the topics we will discuss are:

  • What is MCB and MCB in Full
  • What is MCB and Its Working
  • What is MCCB and Its Function
  • The Main Differences Between an MCB and an MCCB
  • How MCBs and MCCBs are Used

What are MCB and MCCB?

Both MCB and MCCB are circuit breakers. A circuit breaker is a safety device that interrupts the flow of electricity in an electrical circuit in the event of an overload or short circuit.

To understand the difference between MCB and MCCB breakers, it is first necessary to see what the initials MCB and MCCB stand for. After that, we will look at what function each gadget serves in an electrical circuit as well as its working.

The full form of MCB in electrical terminology is a miniature circuit breaker. The full form of MCCB, on the other hand, is a molded case circuit breaker. As their names suggest, these two devices are used to break electrical circuits

MCB Working Principle

The MCB working principle is very simple. It is an electrically operated switch that automatically breaks the circuit when the current flowing through it exceeds a certain preset value.

To perform its function, the MCB uses a tripping mechanism consisting of a bimetallic strip, solenoid, or, most of the time, both. During a fault event such as overcurrent, this MCB tripping mechanism opens contacts, thereby breaking the circuit.

MCCB Working Principle

The working principle of an MCCB is similar to that of an MCB. In fact, a MCCB can be called an advanced mini-circuit breaker. Both devices open an electrical circuit when the current flowing through them exceeds a certain preset value, or when a user manually operates them.

During an overcurrent, the MCCB bimetallic strip heats up while the electromagnetic coil produces a magnetic flux from the excess current. These happenings operate the tripping mechanism that opens the contacts, thus breaking the circuit.

MCB inside parts
MCB inside parts
Resource: https://www.youtube.com/watch?v=-Et8EMZeLiA


We have already covered how each works, but what is the difference between MCB and MCCB circuit breakers? Although both breakers perform almost similar functions, there are some notable differences: The key MCB MCCB differences are outlined below.

MCB vs. MCCB: Interrupt Current Rating

MCB and MCCB ratings for interrupt currents differ significantly. An MCB can interrupt currents up to 1800A while an MCCB can interrupt currents of up to 200kA.

This means that MCCBs are more suitable for use in heavy-duty applications, such as those involving higher loads. An MCB breaker, on the other hand, is most suited for domestic and light commercial applications.

MCB vs. MCCB: Maximum Current Rating

Another MCB vs. MCCB breaker difference is their maximum current rating. An MCB can handle a maximum current of 100A while an MCCB can handle currents of up to 200A.

As such, you can use an MCCB for applications that require higher currents than an MCB can handle. These include heavy-duty industrial applications that involve large equipment like pumps, compressors, and motors.

MCB vs. MCCB: Tripping Characteristics

The tripping characteristics of an MCB and an MCCB are also different. A miniature circuit breaker mostly does not allow the tripping circuit to be varied for different loads and currents. However, this is possible with an MCCB.

In other words, you can use an MCCB to tailor the circuit breaker’s tripping characteristics to the specific needs of your application. This flexibility is typically not available with an MCB.

MCB vs. MCCB: Size

One of the most obvious MCBs and MCCBs differences is their size. As we have seen, an MCB is smaller in size as compared to an MCCB. The smaller size of MCBs makes them more suitable for domestic and small commercial applications.

MCCBs, on the other hand, are larger in size. The larger size of MCCBs makes them more suitable for medium and large commercial applications, as well as heavy industries

MCB vs. MCCB: Price

Another MCB vs. MCCB breaker difference is in their prices. MCBs are less expensive as compared to MCCBs. This is due to the fact that MCBs are smaller in size and have fewer features as compared to MCCBs.

MCCBs, on the other hand, are more expensive as compared to MCBs. This is due to the fact that MCCBs are larger in size and have more features compared to MCBs.

The above-mentioned are the key MCB MCCB differences. Electricians must take these differences into account when selecting the breakers or an electrical system will not function properly. But when do you choose one over the other?

MCB on electrical distribution box
MCB on electrical distribution box
Resource: https://www.youtube.com/watch?v=4JPapPYk8Bw


Now that we have seen the difference between MCB and MCCB breakers, let us answer the question: which one should you use, an MCB or an MCCB?

The answer to this question depends on the application. As we have seen, both miniature circuit breakers and molded case circuit breakers are designed for low-voltage systems. However, you can only use them in different applications.

MCB Application

Some of the suitable uses of miniature circuit breaker devices (MCBs) include homes, offices, commercial buildings, and even light industry systems with low currents and voltage.

In these situations, the miniature breaker will protect the system against overloads and short circuits. An MCB is, thus, a good choice for protecting control panels and distribution boards.

MCCB Application

On the other hand, molded-case circuit breakers (MCCBs) are better suited for use in heavy industries where there are high currents and loads. These are situations that require high interrupting capacity.

Some of the suitable applications for MCCBs include hospitals, data centers, and other similar commercial buildings where a lot of power is consumed.

MCCBs are also a good choice for protecting generators, transformers, and motors against overloads and short circuits.


In conclusion, the key difference between MCB and MCCB breakers is that MCBs are designed for low-current applications while MCCBs are meant for high-current or high-load applications. An MCB is a good choice for protecting homes, offices, and commercial buildings against overloads and short circuits. On the other hand, an MCCB is a better choice for use in heavy industries where there are high currents and loads.

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