Types of Miniature Circuit Breakers & Their Functions

Every home and commercial building requires miniature circuit breakers to protect both the circuit and the occupants. An MCB protects the circuit from overload and short circuits. It is a much safer and effective system compared to the traditional fuse. It is also a more convenient option.

Types of MCBs

MCBs are classified into two main different categories based on two factors:

• Tripping characteristics
• Working principle

Tripping Characteristics

There are three sub-types of mcb circuit breaker based on their tripping characteristics.

• Type B: Such MCBs will trip around if the load current is 3 to 5 times the normal level. They Type B devices are mostly used in homes or for light commercial purposes. The level of surge current is usually low in such cases.
• Type C: This type of MCB is designed to trip when the load current is 5 to 10 times normal. It is commonly used in industrial applications where there is risk of higher loads. Fluorescent lights and inductive appliances are the common connected loads for this type of circuit breaker.
• Type D: This type of mccb circuit breaker will trip if the load current is 10 to 20 times the normal. They are designed for use in commercial and industrial settings where the risk of current surge is very high. If your establishment is using heavy machines, this is the type of MCB you should be using.

MCBs by Working Principle

Based on working principle, there are two types of miniature circuit breakers. The two working principles are:

• Thermal Effect due to overload current: It makes use of a bimetallic strip. If there is over current, the strip gets heated. This causes it to bend and deflect, which releases a mechanical latch. The operating mechanism will open the MCB’s contacts.
• Electromagnetic effect due to overload current: When there is over current, it can also cause electro-mechanical changes in the plunger in the solenoid. When the trip lever gets struck, the latch mechanism releases and the circuit breaker contacts get opened.

The best quality mcb electrical breakers are designed to trip within tenth of a second.

MCBs Based on Number of Poles

There are also different types of MCBs based on the number of poles they have.

• Single Pole: These types of MCBs are designed for providing protection on single-phase of the circuit.
• Double Pole: They provide protection for the neutral and one phase.
• Triple Pole: The three-phase mccb circuit breaker is designed to provide protection on 3 phases but not on the neutral.
• Three-Pole with Neutral: It will provide protection on all 3 phases and the neutral. The protection on the neutral can only be switched to, as it is a separate pole.
• Four-Pole: This type of MCB also provides protection on the neutral along with the 3 phases. It is used in applications where there is risk of high neutral current flow.

These are the different types of miniature circuit breakers available for residential and commercial applications. You should choose the right type based on the kind of circuit you have in your building and the kind of applications.