1S25 Arc Flash Monitor – 8 point sensors / 4 zones


Arc fault protection is a relatively new technique employed for the fast clearance of arcing faults on BUS bars & within metal clad switchgear & associated cable boxes. The arc is detected using an optical sensor & the signal input to a protection device which also monitors the load current on the system. When an arc fault start current is coincident with a signal from the optical sensor a trip command is output. A trip signal can be achieved within 10ms which can be considerably faster than that provided by a traditional IDMT overcurrent relay. This is because the onset of an arcing fault can occur at relatively low fault currents. Arguably the greatest risk of arc fault damage exists at the CB cable termination & in the CB chamber itself due to the slow clearance times of the IDMT feeder protection.


  • Four independent arc fault tripping zones
  • 1 or 2 arc fault sensors per zone allowing up to 8 arc fault sensors per 1S25 module
  • Trip indication LED for each arc fault monitoring zone
  • Non volatile memory ensures last recorded alarm states are restored on power up
  • Nine high speed arc fault tripping duty output contacts (Set for latching or self reset)
  • Zone segregated or common tripping output configuration
  • Continuous arc sensor supervision with sensor fail LED for each zone
  • Wide range status input to block arc fault monitoring
  • Front panel reset button & status input
  • Self supervision watchdog with healthy LED & alarm contact
  • Built in test sequence
  • Wide range auxiliary supply
  • Made in Australia





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