The difference between molded case circuit breaker and miniature circuit breaker

Update date:2017-11-18 Source:MAXGE

The main function of moulded circuit breaker (MCCB) is to provide protection function for the overload and short circuit in the protection circuit of low-voltage power distribution system and motor. Due to its reliability and stability, it has been widely used in industry. The miniature circuit breaker (MCB) is also a large circuit breaker with a wide range and quantity. The main function is to provide protection for electrical terminal power distribution devices. Since both of them belong to the circuit breaker and the plastic-shell circuit breaker is mostly used for small capacity, it is very practical and important to choose the right products to understand the difference between them. Here's a quick explanation.


Let's start with the basic similarities, because both of them belong to the circuit breaker, and they need to ad here to some basic product standards and have the same working principles. Then, the difference between the two is, in general, the following points:


1.Current rating

The maximum current level of the miniature  breaker is within 125A. Because both of the capacity gap, in specific work, the effective area of molded case circuit breaker is greater than the miniature circuit breaker, at the same time, access to the wire is thick, can reach more than 35 square, and miniature circuit breaker is only suitable for wire under 10 square. So general for indoor situation, the room is bigger more appropriate choose moulded case circuit breaker.



The moulded circuit breaker is mainly screws, easy to press, good contact and stable operation. The miniature circuit breaker is mainly installed through the guide rail, and sometimes the contact is bad due to lack of torque. Because of the different installation methods, the installation of the molded case circuit breaker is more stable than the small circuit breaker, and the difficulty is lower.

3.Operation and life

 Two sets of devices are used to protect the overflow and short circuit of plastic shell breaker, and the flow protection action value can be adjusted manually and quickly. Miniature circuit breakers are used to share a set of current and short circuits, which can not be adjusted to solve problems. The plastic shell circuit breaker is large and close, with an arc extinguishing and arc extinguishing. It can withstand a larger short circuit current, and it is not easy to cause interphase short circuit, thus the service life is also better than the miniature circuit breaker.


4.Use flexibility

In this case, the plastic case breaker is more prominent, and its flexibility is better than the miniature circuit breaker. The overcurrent and short-circuit protection devices of the molded case circuit breaker are independent, and the operation value of the flow protection can be adjusted flexibly. The overcurrent protection and short circuit protection of miniature circuit breakers are unified devices, and there are some deficiencies in the adjustment of flexibility.


According to the above situation, it seems that the miniature circuit breaker is in the downwind, but it is necessary to select the miniature circuit breaker for some time. For example, the safety of the line should be improved because of the high sensitivity of the miniature circuit breaker and fast breaking of the circuit, which is more conducive to the protection of the circuit and electrical appliances.

Thus can see both have their own advantages and is suitable for use, the key is to fully understand the difference of molded case circuit breaker and miniature circuit breaker, and to choose according to their own needs.

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