GNM2 series moulded case circuit breaker (hereafter reffered to as simply breaker),whose insulated voltages 800V,suitable for conversion and starting a motor not frequently in the circuitof 50Hz AC (or 60Hz) rated working voltage 690V,rated working current up to 1250A,The breaker have overload,short circuit and under-voltage protection device,which protects the circuit and power equipment against damage. According to level of the breaking capacity of rated maximal short circuit, the breaker can be classified into two types, Type L(Standard type),Type M(Higher breaking type), Such breaker possesses the features such as compactness, high breaking capacity, short arc-cover and shock resistance, etc. The breaker can be installed vertically (upright) as well as horizontally (crosswise). The breaker has disconnecting function,its corresponding symbolis hownas? ? The breaker measre up;IEC60947-2 GB14048.2