Overhead and Underground fault passage indicator (FPI / FCI)


Directional and Amperometric Fault Passage Indicators or Fault Current Indicators for medium voltage overhead and underground networks.

Main characteristics

Installed in MV/LV distribution substations, LV cut-off cabinets or online support posts, the SENTINEL  fault passage indicators range can locate faults on the overhead or underground MV network, including single phase grounded faults and multiple phase transient and permanent faults.

These fault passage indicators quickly identify faulty network sections by providing information about permanent faults and a count of all events that have occurred.

Available in a Directional or Amperometric version depending on the grounding of the neutral conductor (impedance, compensated, direct, etc.).

Each fault passage indicator has:

  • A two-colour indicator for signalling permanent faults
  • Relay outputs for signalling transient and permanent faults or a failure of the fault passage indicator itself
  • A user interface
  • A radio remote control for consulting and configuring remotely (optional for the overhead version)
  • A set of 3 open-ended moulded cores for single-core cables (underground version)
  • Open-ended moulded core for three-core cables (optional for the underground version)
  • Magnetic and electric field sensors, internal to the housing (overhead version)


  • Less time required for locating faulty network sections thanks to the presence of indicator lights showing the fault
  • Avoids detecting defects by successive resets, which tend to lessen the lifetime of network equipment (stress due to faulty resets)
  • Complete range adapting to all neutral states and all voltage levels
  • Optional remote control for the overhead versions, for configuring and viewing the fault passage indicator remotely (convenient when the installation height does not allow for easy accessibility)
  • Low flow communication option Sigfox and LoraWan


  • Public distribution network
  • Private substations

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