ABB miniature circuit breaker Sh200 series is a branch of S200 series, belonging to the same generation of products. The difference between Sh200 series and S200 series is that some mechanisms that can add accessories are removed, the internal structure is simplified, and the cost of products is reduced. So Sh200 series is also known as building type special miniature circuit breaker (generally, the miniature circuit breaker used in buildings does not need the function of adding accessories). Sh200 series is a miniature circuit breaker, which can be used to distribute electric energy, start asynchronous motor infrequently, protect the power line and motor, and cut off the circuit automatically in case of serious overload, short circuit, undervoltage and other faults. Its function is equivalent to the combination of fuse switch and overheating relay

在民用建筑设计中低压断路器主要用于线路的过载、短路、过电流、失压、欠压、接地、漏电、双电源自动切换及电动机的不频繁起动时的保护、操作等用途，其选择原则除遵守低压电器设备的使用环境特征等基本原则（见工业与民用配电设计手册）外尚应考虑如下条件：

In the design of civil buildings, low-voltage circuit breakers are mainly used for overload, short circuit, over-current, loss of voltage, under voltage, grounding, leakage, automatic switching of dual power supply and protection and operation of motor when starting infrequently, In addition to the basic principles such as the operating environment characteristics of low-voltage electrical equipment (see industrial and civil power distribution design manual), the following conditions should also be considered for the selection:

断路器的额定电压不应小于线路额定电压；

The rated voltage of circuit breaker shall not be less than the rated voltage of line;

断路器额定电流与过流脱扣器的额定电流不小于线路的计算电流；

The rated current of circuit breaker and over-current release shall not be less than the calculated current of line;

断路器的额定短路分断能力不小于线路中短路电流；

The rated short-circuit breaking capacity of the circuit breaker shall not be less than the short-circuit current in the line;

选择型配电断路器需考虑短延时短路通断能力和延时保护级间配合；

The short-time short-circuit on-off capability and the coordination between delay protection levels should be considered for the selective distribution circuit breaker;

断路器欠压脱扣器额定电压等于线路额定电压；

The rated voltage of under voltage release of circuit breaker is equal to the rated voltage of line;

当用于电动机保护时，则选择断路器需考虑电动机的起动电流并使之在起动时间内不动作；设计计算见“工业与民用配电设计手册”；

When the circuit breaker is used for motor protection, the starting current of the motor should be considered and the circuit breaker should not operate within the starting time; See "industrial and civil power distribution design manual" for design calculation;

断路器选择还应考虑断路器与断路器、断路器与熔断器的选择性配合。

The selection of circuit breaker should also consider the selective cooperation between circuit breaker and circuit breaker, circuit breaker and fuse.