Trailblazing systems for a safer and greener world

Trailblazing systems
for a safer and greener world


90-240 V AC/DC

Trench’s Earth fault detection system is used to reliably locate the faulty feeder for both high and low impedance faults increasing safety and the efficiency of the system.


  • All-purpose controller for different brands of load-adjustable ASC
  • Built-in display
  • Can be installed in a standard 19″ rack
  • Available as a combined control and detection unit


  • Faulty feeder detection during Earth Faults
  • Power distribution network
  • Compensated (Resonant earthed) electrical systems


Any ASC brand, maintenance free and easy to handle

EFD 500

Fulfills the highest requirements in the selective detection of earth faults. The combination of the admittance method with additional algorithms, offers reliable and selective earth-fault detection.

EFD 500c

With all the features of the successful EFD 500, Trench developed an alternate with the EFD 500c - a compact device with control & detection capabilities.

Ease of use

The EFD 500 and EFD 500C are easy to use due to integrated displays, scroll wheels and clear function keys. They can be remotely controlled and have additional displays for control and detection modes.

Design Features

Microprocessor based flexible hardware configuration, 19‘‘-rack mountable and extended operations via PC by a terminal program are some advantages of the EFD 500 and EFD 500C.

Hardware Options

Includes alternative power supply, optical port for serial communication and IEC61850 communication port, RJ45, .