3EL2 surge arresters and 3EF surge limiters

Surge arresters and limiters protect devices and switchgear by discharging overvoltages caused by lightning strikes, switching operations, or earth faults. They ensure that the arising overvoltages will not exceed the permissible withstand voltages of the equipment to be protected.


  • Reliable protection of sensitive equipment against overvoltages from the grid or switching operations

  • Low protection levels and a fine grading of the rated voltage

  • 3EF1 surge limiter version for cable systems up to 15 kV

  • 3EF3 surge limiter version for power plants and extended cable systems with higher energy absorption capability

  • 3EK7 surge limiter version for the transition point between cables and overhead lines

  • Long years of tightness by means of a hermetically sealed porcelain housing, outdoor-resistant light metal alloy and ozone-resistant seals (3EE)


  • Protection of sensitive equipment such as rotating machines or other devices with windings exposed to the air, e.g. protection of motors, generators and transformers against internal and external overvoltages

  • Use in cable systems, generally in indoor switchgear

  • Protection against overvoltages due to lightning strikes in overhead lines

  • Protection against internal overvoltages due to switching operations or earth faults

3SV 9 auxiliary switches

The auxiliary switch is a switch to be operated mechanically for a short or continuous contact command. It is integrated in the secondary circuit of circuit-breakers of different characteristics as well as in electromagnetic interlocking systems.


  • Auxiliary switch without latches and stops, for mechanical operation

  • Can be used for any rotation angles

  • Can be ordered with switching levels from 2 to 26; whereby these can be configured individually

  • The switching levels can be freely configured as NC, NO or changeover contacts. Moreover, different switching angles and contact overlappings can be selected

  • The device conforms to the standards IEV 947 Part 3, Part 5-1 and DIN VDE 0660 Part 107, as well as IEC 721 Part 3-3


  • Use in the secondary circuit in a wide variety of circuit-breakers from different manufacturers

  • Mutual electrical interlock of electromagnetic interlock systems

  • Operation of auxiliary contactors, magnet coils, and releases

  • Operation of circuit-breaker motor operating mechanisms