The Ex9UE2 line is a group of Class II Surge Protective Devices. hey are intended as a protection against transient overvoltage caused by fast switching operations or indirect hits of lightning strokes (residuum effects). It is recommended to install Class II SPDs every 10 – 20 meters of cable length repetitively, typically to main and sub distribution boards. The Ex9UE2 20 440 are designed for direct coordination with Class I SPDs ofline Ex9UE1 35. In case of Ex9UE2 20 275, the coordination with the line Ex9UE1 35 is done by means of 10 m cable length. The design of Ex9UE2 is based on Metal Oxide Varistors. Such design provides very low response time. The modular design with plug in inserts allows simple and quick replacement of function modules in case of MOV is beyond if its lifespan due to often occurrence of overvoltage peaks.