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difference between MCCB and ACB
This image shows the size difference between MCCB and ACB
Resource: https://www.youtube.com/watch?v=zNaV-z8R1oI

What is the difference between MCCB and ACB? Granted, both are protective circuit breakers. But while they share protection similarities, the two breakers also present notable differences, as this post will help you find out. The post expounds on the MCCB ACB difference as well as the application details of the two devices.

Meaning of MCCB

Let’s start with the meaning of MCCB and ACB. Or, in other words, what the ACB and MCCB abbreviation stands for. After that, we will compare the differences between the two types of circuit breakers. Then, we’ll explain which situation requires which device.

MCCB Full Form

MCCB stands for (or is an abbreviation for) Molded Case Circuit Breaker. The word molded, as you would expect, refers to the fact that MCCB circuit breakers come with molded plastic or resin housings or enclosures.

The plastic is usually flame resistant, heat resistant, and highly insulating. This makes the breaker suitable for use in different environments, including industrial-grade applications.

The ACB Full Form

ACB stands for Air Circuit Breaker. Just like the MCCB breaker, the ACB derives its name from the fact that it uses air for insulation. In terms of construction, the ACB is made from a steel metal frame and the tripping mechanisms housed inside it.

ACBs are mainly built for use in high current applications such as power transmission lines and heavy industrial systems. In these cases, the ACB offers both overload and fault protection of the circuit – the same way that the MCCB protection does.

MCCB sizes
Different molded case circuit breakers, MCCB sizes
Resource: https://www.packworld.com

Difference Between MCCB and ACB

After the technical definitions, let’s discuss the differences between the MCCB vs. ACB breaker. This will help make the decision of which type to use for any particular application easier. The ACB vs. MCCB comparison will include these differences: ratings, size, and operating, voltage, and cost.

ACB and MCCB Difference #1 Ratings

One of the most significant differences between MCCB and ACB is their ratings. The MCCB ratings for current usually range from a few amperes up to 800A, while ACB ratings for can go up to 6,300A.

That means an ACB has a much larger current-carrying capacity than an MCCB and, therefore, used in applications that involve large amounts of current, such as power distribution systems or equipment and substations.

ACB and MCCB Difference #2 Size

In terms of physical size, an ACB is larger than an MCCB. MCCB dimensions are generally three to four times less than those of ACBs. This is not to be confused with MCCB frame sizes, which is the industry language for the maximum current rating range of the device.

Molded case circuit breakers do not need to be as large as ACBs. This is because they’re designed for use in lower current applications. The smaller MCCB sizes also make them suitable for installations in places where space is limited, such as in the panel boards of residential buildings and small industrial plants.

ACB and MCCB Difference #3 Operation

While both types of circuit breakers interrupt the circuit when a fault occurs, one offers more control and protection than the other. In essence, the MCCB operation is composed of fewer features when compared to the ACB.

In addition, the user can also add more accessories to an ACB than an MCCB. These include auxiliary contacts and other release accessories. As a result, the operation on MCBs is less complex and less powerful than that of an air circuit breaker.

ACB and MCCB Difference #4 Voltage

Another MCCB and ACB difference lies in the type of voltage they are rated for. ACBs can handle high-current/voltage applications. In contrast, MCCB circuit breakers are usually designed to work with lower voltage circuits than ACBs.

Practically, MCCBs are built for use in systems with voltages of 120V, 240V, and 380V up to 660V whereas ACBs are suitable for voltages of up to 1140 volts. As you can tell, these mostly include power distribution lines and systems.

ACB and MCCB Difference #5 Application

The function of MCCB and ACB is to protect electrical systems and electrical equipment from damage by faults. However, because the breakers come with different voltage/current ratings, they are also used in different kinds of applications.

MCCBs are typically installed in residential and commercial or industrial facilities, such as the mains circuit of retail stores, factories and homes. In comparison, ACBs are more common in industrial applications. These include substations, power plants and high-voltage grid systems.

This difference between MCCB and ACB circuit breakers is due to their different capacities. Since MCCBs are usually rated up to 800A while ACBs range up to 6,300A, they can handle higher currents in high voltage systems.

ACB and MCCB Difference #6 MCCB Cost

In terms of price, an MCCB breaker is usually cheaper than an ACB. That’s because MCCBs have a lower current-carrying capacity and smaller size. However, the cost differences between the two circuit breakers depend on their ratings and manufacturer.

In general, MCCB prices mainly range around $200, while ACB prices can reach over $500. That said, prices are dependent on the features and specifications of each device. Also, different manufacturers might have different prices for their products.

MCCB panel board
MCCB panel board
Resource: https://www.youtube.com/watch?v=zbttEkUfHpw

When to Use ACB and MCCB

Overall, it is important to understand that MCCBs and ACBs are designed to serve different purposes. While MCCB uses can cover residential, commercial, and industrial applications, ACBs offer greater control, protection and flexibility in high current industrial environments.

It’s, therefore, essential to choice the right breaker type for your needs.

  • For example, if you need to protect low voltage circuits with current ratings of up to 800A, then an MCCB circuit breaker would be the best option.
  • On the other hand, if you require protection for high-voltage systems with current ratings over 800A, then an ACB is your best option.

Regardless of the type you choose, it’s advisable to ensure that their ratings are suitable for your intended application. This will help prevent any potential damage to your system in case of a fault or voltage surge.


In conclusion, understanding the difference between MCCB and ACB circuit breakers is essential for any electrical wiring project. Both types of breakers are reliable and effective at providing overload protection, but they each have different applications.

ACBs offer higher current-carrying capacity and are more expensive than MCCBs, which are smaller and cheaper. In the end, it is important to consider the specific needs of a project before choosing one over the other.

IGOYE Molded Case Circuit Breaker Catalog