3HM3 series moulded case circuit breaker，it’s applicable circuit of AC 50Hz(or 60Hz)，rated insulation voltage 660V，rated operating voltage under AC 660V，250V(DC)，rated operating current 1OA-800V，for distribute energy of electricity and infrequent making and breaking circuit．in normal conditions．The MCCB rated current under 400A they are provided with the function of the protection against overload and short circuit and undervoltage．The MCCB complies with standard of IEC 947-2．GBl4048.2，GBl4048.4 and so on．
Classification of MCCB
Installation type of MCCB：MCCB are suitable for vertical or harizontal installation．
According to use of MCCB：Distribution circuit protection type，motor protection type；
According to connection way：Front panel connection，Back panel connection，Plug-in connection；
According to operation way：For direct handle operating；For external rotary handle operating；For motor operating；
According to overload release type：Magnetic release(only instantaneous)the modynamic type (dual)
According to number of poles：Two poles，Three poles，Four poles；
The neutral pole(N pole)of four pole MCCB has four types：
Type A：No overload release on N pole，which is making at all time；not closing and opening with the other three poles．
Type B：No overload release on N pole．which closing and opening with the other three poles．
Type C：With overload release on N pole．which closing and opening with the other three poles．
Type D：With overload release on N pole．which making all time；not closing and opening with the other three poles．
Type E：With a neutral pole interruption protector on N pole that closing or opening with other three poles．