The Different Types of MCCB and How It Works

17th Feb 2024

There are different types of circuit breakers, and you need to know how they work in order to install them correctly. These circuit breakers are grouped into different types: type B, type C, type D, type K, and type Z. A type B MCCB will trip when it sees a surge of 3 to 5 times the rated current, while a type C will trip when it sees a surge 5 to 10 times.

An MCCB is an excellent electrical protection device. Its casing is sealed and cannot be opened. But just like any other electrical equipment, it requires periodic maintenance in order to function properly. 

MCCBs can handle a large current and a short circuit. They also have a movable trip unit and a short tripping time. Some types have remote ON/OFF features, making them useful in industrial settings where electrical shocks are a common hazard.

Different types of MCCBs are used in different electrical settings. If you want to know about the different types of MCCBs and how it works, continue reading this article. 

TSM8 molded case circuit breaker
Moulded Case Circuit Breaker

How does MCCB Works?

If you’ve ever wondered How MCCB Works, you’ve come to the right place. There are several important parts to know. The first one is the relay tripping unit, or brain, of the MCCB. This component contains an electromagnetic coil and a tripping plunger, which is used to trip the breaker on a predetermined time delay when a fault condition is detected. When an overload occurs, the MCCB trips.

The second part of the MCCB system protects against overloads by using temperature-sensitive components. These components consist of a bimetallic strip that bends due to the different expansion rates of the two metals. As the total current exceeds the value of the trip, the bimetallic strip will begin to heat up and bend, allowing the electrical current to flow through. If the current is allowed to flow without stopping, the device will cause an electrical fault.

Another component is the arcing contacts. These are thin and light and can interrupt an arc in about one-half to two cycles. An arcing contact is made of a harder alloy than the main contacts. This contact extends ahead of the main contacts and touches them afterward. The main contacts are used to carry load current and can be adjusted to prevent overloads. 

An MCCB is also used to protect against short circuits. Its solenoid generates an electromagnetic force, which repels the plunger that is responsible for tripping the circuit. When it senses a fault, the MCCB will turn off the current. This mechanism prevents electric shock, so it is a vital part of electrical safety. There are many different types of MCCBs, and it’s important to choose one that best suits your needs.

Choosing the Right Type of MCCB

If you’re wondering what MCCBs are, you’re not alone. It’s not uncommon to find them in industrial and commercial settings. Some electricians even include them in their projects. Basically, they’re circuit breakers that trip when an electrical overload or short circuit occurs, protecting the circuit from damage. Read on to learn more about the different types, and choosing the right mccb for your needs.

  • Type B

An MCB is a device that shuts off a circuit if a power source exceeds a set limit. A Type B MCCB trips at 3 to 5 times its rated input. Type B MCBs are used for applications where the load current is low, and there is a low inrush current. They protect against overloads and short circuits while allowing for the safe operation of electrical equipment. They are sensitive enough to trip at a 3 to 5 times higher than their rated maximum.

  • Type C

The Type C of MCCB is designed to protect electronic circuits from overcurrents. This type of MCB is a good choice for commercial units, as it provides protection against short-circuits. It trips between 5 to 10 times the rated current. The Type C of MCCB is suitable for most types of applications but may be too expensive for certain applications.

  • Type D

A Type D of MCCB is an overload-protection device. Its operating mechanism uses an electromagnetic device and a temperature-sensitive device to protect from overcurrent and electrical faults. A Type D breaker is specially designed for industrial use. Its operating range is 10 to 20 times the full load current and time delay of 0.04 to 3 seconds.

  • Type K

An MCCB is a circuit breaker that protects electrical circuits from damage by tripping when the input current exceeds the rated limit. The K-type MCCB provides the best protection for two cables and trips at a rate of 8 to 12 times the full load current.

  • Type Z

A Type Z MCCB can be used for a variety of applications. Its MOC (Maximum Overload Current) determines how long it will remain operational after an overload. A Type Z MCCB is also considered to be one of the most sensitive types, with its threshold set at thrice the current rating. While type Z is not as versatile as the other two types, it can protect sensitive equipment.

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