Sigma Modular

Programmable Earth Fault or Overcurrent and Earth Fault Indication
with comms option

Sigma offers a flexible solution to CFI requirements. As a modular device, it can be built up and priced according to the client's needs. It may have a single Earth Fault card or add three phase cards to give it an Earth fault and overcurrent capability. It is programmable for all key functions, including CT compatibility. Pre-loaded or selectable profiles, set up for the client's preferred settings ensure minimal programming intervention. Load current monitoring is available from LV-powered Sigma's and an integrated communications option may be added for GSM or GPRS remote reporting of alarms and status. Sigma may be used with conventional resin cast CTs, or with Bowdens flexible band CTs which are designed to fit into the cable box of an RMU.


  • Overcurrent and Earth Fault
  • Programmable for all key functions
  • Powered from a 10-year lithium battery or LV Mains or RTU supply
  • LV Reset or LV Sensor reset/monitoring
  • Modbus serial interface for RTUM
  • Optional GSM/GPRS comms module
  • CT matching feature for compatibility with all CTs
  • Alarm relay outputs
  • Band sensor CT or Cast Resin CT