The Ex9UE1+2 25 line is a group of Class I+II Surge Protective Devices. They are intended as a protection against direct hit of lightning strokes of medium intensities. In standard three phase TN-C grid, they provides protection up to LPL I, II requirements given in EN 62305 with total lightning current introduced into electrical installation of 75 kA and total lightning stroke current 150 or 200 kA based on physical configuration and mutual position of grounding point of lightning rod, grounding point of the electrical installation and place of SPD installation.
The design of Ex9UE1+2 25 is hybrid based on combination of high energy Metal Oxide Varistors and isolation Spark Gap. This combination brings lower response time thanks to fast MOV and low voltage SG in comparison to a pure SG solution. The serial connection of MOV provides limitation of follow current characteristics for SG, but also full isolation due to serial connection of SG to MOV.
The main characteristics are defined by MOV part dominantly. Resulting protection level and response characteristics not only fulfill requirements of class I SPDs but also for class II ones. Ex9UE1+2 25 provides protection for both classes I and II. 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 high intensity or often occurrence of overvoltage peaks.