Moulded case circuit breaker (MCCB) is widely used as a kind of circuit breaker like frame circuit breaker. So what are the differences between these two kinds of circuit breakers in the process of practical application? Here is a brief analysis of ABB moulded case circuit breaker agent introduced to switch factory for us.

1.塑壳断路器采用的是塑料化结构，它的特点是断路器外壳和框架都采用的是塑料压制而成，并且它将触头、灭弧系统等都放在了一个绝缘小室中，以防止其之间发生短路，并为了确保电弧能够向上喷出，保证了触头系统可靠分断。而框架断路器采用的则是模块化结构，它分为框架、触头灭弧系统、手动操作机构、电动操作机构、智能型 控 制器以及抽屉座等结构。并且其每个部分均可成为一个完整独 立的部件，组装时只需1-2个螺钉即可将其固定，拆装也十分方便，便于其检修维护。

1. The moulded case circuit breaker adopts the plastic structure, which is characterized by that the shell and frame of the circuit breaker are made of plastic pressing, and it places the contact and arc extinguishing system in an insulated chamber to prevent short circuit between them, and ensures the reliable breaking of the contact system in order to ensure that the arc can be ejected upward. The frame circuit breaker adopts modular structure, which is divided into frame, contact arc extinguishing system, manual operation mechanism, electric operation mechanism, intelligent controller and drawer base. And each part can be a complete and independent component, which can be fixed with only 1-2 screws during assembly. It is also very convenient for disassembly and assembly, and convenient for maintenance.

2.塑壳断路器的产品种类繁多，其特点是结构紧凑，操作容易，其结构与功能也比较简单。而框架断路器则功能完善，特别是近年来的单片机技术的广泛应用，从而使框架断路器逐步朝着高性能、易维护、网络化的方向发展。

2. There are many kinds of moulded case circuit breakers, which are characterized by compact structure, easy operation, and simple structure and function. The frame circuit breaker has perfect functions, especially the wide application of MCU technology in recent years, which makes the frame circuit breaker gradually develop in the direction of high performance, easy maintenance and networking.

3.在额定电流上，塑壳断路器一般为630A以下，而框架断路器的额定电流要大很多，一般为630A-6300A。

3. In terms of rated current, moulded case circuit breaker is generally less than 630A, while the rated current of frame circuit breaker is much larger, generally 630a-6300a.

4.而在分段能力上，框架断路器要比塑壳断路器高。一般情况下，800A以上的回路或分段能力要求比较高的回路大多采用的是框架断路器，而630A以下的回路，则一般使用塑壳断路器。

4. In terms of sectional capacity, the frame circuit breaker is higher than the moulded case circuit breaker. Generally speaking, the circuit with more than 800A or the circuit with higher requirements for sectional capacity is mostly frame circuit breaker, while the circuit with less than 630A is generally molded case circuit breaker.

5.框架断路器的所有零件都装在一个绝缘的金属框架内，常为开启式，可装设多种附件，其更换触头和部件也较为方便，多用在电源端总开关。而塑壳断路器的接地线端子外触头、灭弧室、脱扣器和操作机构等都被装在了一个塑料外壳内，一般情况下我们不考虑其维修，它比较适用于作支路的保护开关，其大部分采用的是手动操作。

5. All parts of the frame circuit breaker are installed in an insulated metal frame, which is usually open type. It can be equipped with a variety of accessories, and it is more convenient to replace contacts and components. It is often used in the main switch of the power end. The external contact of ground wire terminal, arc extinguishing chamber, release and operating mechanism of MCCB are all installed in a plastic shell. Generally, we do not consider its maintenance. It is more suitable for branch protection switch, and most of them are operated manually.