What Is The Difference Between MCB and MCCB?

Most of us have heard the terms “MCB” and “MCCB” at some point of time. But as a layman, we could hardly differentiate between them. Even though both MCB and MCCB are circuit breakers, there are some specific differences which make them apt for particular use. First of all, let’s understand what the abbreviations MCB and MCCB stand for. The MCB stands for “Miniature Circuit Breaker”, while the MCCB for “Molded Case Circuit Breaker.” Before moving on to know the key differences, get acquainted with the fundamentals of MCB and MCCB.

What is a Miniature Circuit Breaker (MCB)?

An MCB, or a miniature circuit breaker, is an automated electrical device intended to protect an electrical circuit from damage caused by excess current, usually occurring from an overload or short circuit. Its fundamental function is to interrupt the current flow once a fault is detected. Its working principle is quite simple. The MCB has two contacts, where one is movable and the other one is fixed. As the current increases from the predefined limit, the movable contacts get disconnected from the fixed contacts, consequently, the circuit gets open and disconnect them from the main supply.

What is a Moulded Case Circuit Breaker (MCCB)?

An MCCB, or a moulded case circuit breaker, is an electric device designed to protect the circuit from overloading. However, unlike the MCB, it is used in places where adjustable tripping is required. Essentially used for high current applications, the MCCB features a manually operated switch for tripping the circuit. Talking about its working principle, the MCCB has two arrangements; one for the over temperature and the other one for over current. It has a bimetallic contact, which expands and contracts with the change in temperature. During the normal operating conditions, the contact allows the current to flow through the circuit. However, if the current rises beyond the predefined limit, the contacts will get warm and expand until they get open. As a result, the circuit gets disconnected from the main supply, protecting the equipment from damage.

Difference between MCB and MCCB

The major difference between MCB and MCCB is their capacity. The MCB rated under 100 amps (with an interrupting rating of under 18,000 amps) doesn’t have an adjustable trip feature. So, MCBs generally cater to low current circuits. Contrastingly, an MCCB that could be rated from 10 and 2,500 amps (with an interrupting rating from 10,000 amps to 200,000 amps) comes with an adjustable trip feature. It is generally meant for high current circuits. If evaluated from their power capacities, the MCB is essentially used for low-current requirements, such as, home wiring or small electronic circuits; while the MCCB is better used for high-power requirements.

Though both are classified under low voltage circuit breakers as per the standards set by IEC 947, an MCCB has much more capacity than an MCB. Adding to the usefulness, some MCCB units have electrical motor operators, which can be tripped using a remote control. For industrial or commercial use, MCCBs can be used as standby power which runs on an automatic transfer switch. Both MCBs and MCCBs are installed in a specific location on the wall, making them easier to install or uninstall without disturbing the entire electricity system or damaging the switchgear. These circuit breakers are designed specifically to handle direct current, and are generally laid out in rows for space efficiency. Once they get “tripped”, circuit breakers are usually reset for further usage.

Last Few Words

To ensure safety while using electricity and electrical equipments, the circuit breakers are installed in the buildings. They make sure to evade fire hazards or other electrical issues by disconnecting the flow of current, the moment they experience a short circuit or an overload. That’s why; both MCB and MCCB should be installed by professionals to minimize the possibility of error. Simultaneously, it’s important to choose the right MCB or MCCB to ensure safety of your loved ones. Havells, the brand synonymous with high-quality electrical goods and switchgear, offers a wide selection of circuit breakers which are suitable for residential and commercial use. The MCBs and MCCBs by Havells are absolutely intelligent and reliable, thus, offer long-lasting performance in safeguarding your haven.