Paidong Industrial Zone Qiligang,Yueqing City,Zhejiang province,China.
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    14 Jul, 2022
    Posted by elcb_admin
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    What Are the Advantages of Miniature Circuit Breaker?

    In the past years, fuses were used for the safety of electrical connections but they were not proved as efficient as they were not sensitive enough to detect small changes in current flows. Also once the fuses have done their job of safety they need to repair by replacing a new piece of electrical wire inside them. But nowadays, more reliable, sensitive, and fast circuit breakers have been developed which are used in the replacement of fuses.

    Introduction to miniature circuit breakers (MCB)

    These are automatic electrical switching devices used for the protection of electrical circuits. Whenever there is a need for safety in electrical circuits these breakers don’t allow the current to flow. For example, in case of a short circuit or overload, the breakers automatically open the circuit to avoid any damage in circuits, to prevent the fire from burning, etc.

    What is a Miniature circuit breaker (MCB)?

    A miniature circuit breaker is an automatic electrical device used for the safety of electrical equipment and appliances when excessive current flows through the circuit or a short circuit occur. It turns the electricity connection automatically OFF when excessive current starts flowing through the circuit and when current flow becomes normal it turns the connection ON again automatically.

    In the modern era of science and technology, everyone should have known the term circuit breaker which is used as an automatic electrical switching device.

    Short circuit rating/Breaking capacity of MCB (Miniature circuit breakers)

    The level of working ability of a miniature circuit breaker is indicated by its short circuit rating. Short circuit ratings of MCB (miniature circuit breakers)are given in kilo Amperes.

    Breaking capacity or short circuit rating ranges of miniature circuit breakers are from 10KA TO 16KA. These MCBs with wide varieties of breaking capacity are used according to the requirements of owners of homes and industries to save the appliances and electrical equipment from damage.

    How does the MCB (miniature circuit breaker) work/ or working principle of MCB (miniature circuit breaker).

    The working principle of a miniature circuit breaker is not complex enough to understand.

    Let me explain it as simply as possible, it works on two effects of electricity overflow.

    1. thermal effect
    2. electromagnetic effect

    Due to the thermal effect of overflow of electricity, the bimetallic strip inside the miniature circuit breaker is bent.

    A bimetallic strip is basically a strip made up of two metals joined together both of the metal strips are of different heat capacities. A metal with less heat capacity reaches to is maximum heat capacity level it tends to expand due to its metallic ductility while a metal with a higher heat capacity doesn’t behave so as a result, a bend in the whole strip occurs, and the bimetallic strip then releases a mechanical latch this mechanical latch is attached with the operating mechanism so, consequently the circuit opens (electric current through the circuit stops flowing).

    on the other hand, when a short circuit(sudden rise in electric current ) occurs, the plunger associated with the solenoid (tripping coil) is displaced electromechanically and strikes the trip lever so that the latch mechanism releases instantly, as a result of which the circuit opens.

    As I have told you before this is a very simple explanation for the working of the miniature circuit breaker.

    Advantages/benefits of MCB (miniature circuit breaker) over fuses

    • Highly current sensitive

    MCBs are more sensitive to detecting changes in current flow than fuses.


    • Quicker response against short circuits

    it responds quickly against short circuits and overload due to its sensitivity.


    • Reusable

    it can be reused as there is no need of changing any wire, unlike the fuses.


    • less maintenance cost

    it has less maintenance cost as compared to fuses.


    • less replacement cost

    its replacement cost is also too much less.


    • More reliable

    MCB are more reliable electrical safety devices as compared to fuses due to their quick response and current sensitivity.


    • Simple to use

    it is very simple for resuming the supply just like a simple ON/OFF switch and can control the circuit switch.


    • Automatic

    It automatically turns off the connections of electricity and supply can be resumed easily again.


    • Agaves more electricity

    It is more electricity safer than handling fuses.


    • Better interface

    It provides a good interface as compared to fuses.


    • Identifies faulty circuits

    If there is a fault anywhere in the circuit, it can be used to identify that specific faulty area.


    • Better performance

    Its performance is good in case of earth leakage and the identification of faulty circuits.


    • Time delay character

    In case of surge current, it can work more properly as it has time delay characteristic.

    Different types of MCBs (miniature circuit breakers) and their area of use.

    Different types of MCBs are named A Type, B Type, C Type, D Type, K Type, and Z Type.

    From the above-mentioned types of MCBs, the key versions of it are B Type, C Type, and D Type. These types of MCBs are designed for the different strengths of the electric surges in different settings.

    Let’s take a look at three main types of MCBs.


    This type of breaker has the tripping current ranging from 3 to 5 times the full load current and operating time ranges from 0.04 seconds to 13 seconds.

    It is designed for domestic circuits and for those commercial circuits where there is a low voltage setting and small surges.

    It is the most sensitive MCB.


    Its tripping current ranges from 5 to 10 times the full load current and its operating time ranges from 0.04 seconds to 5 seconds.

    it is designed for industrial and commercial circuits, where any surges are relative to be higher.

    it is less sensitive than B-Type MCBs.


    the tripping current ranges of D-type MCB is from 10 to 20 times the full load current and its operating time ranges from 0.04 seconds to 3 seconds.

    It is designed for heavy devices used in industries, for example, x-rays machines, large motors, power supply units, etc.

    it is least sensitive than all previously described MCBs.


    It will Tripp when the current reaches its recommended maximum value eight to twelve times.

    it is useful for the safety of motors.


    it is a highly sensitive miniature circuit breaker made up of the most sensitive devices like semiconductors. It is tripped when the current reaches its recommended load only two to three times.

    Miniature circuit breaker mcb graphics
    Miniature circuit breaker mcb graphics

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