Nominal voltage6 kV to 110 kV
    SensitivityShows faults from 0.5 A
    Fault indicationBright LED
    Shows the faulty phase
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  • For outdoor use in tropical climate
  • High strength plastic of UV stabilized and flame retarding type
  • Metal parts such as spring and bar are made of stainless steel
  • Key features

    CL25 Fault Indicator is an electronic device, which is intended for use in medium voltage overhead lines.

    CL25 senses current on the phase where it is installed. Indication is triggered when it detects a faulty current, above the current threshold, passing in the line conductors.

    Streamer Fault Passage Indicator CL is designed in such a way as not to react on inrush current. So-called inrush resistance is the parameter, which helps to restrain triggering due to transformer’s magnetizing current or switching a load.

    CL25 is suitable for use on multiple lines supported by the same pole.

    CL25 is provided with a battery control. When the battery capacity is below 20% of nominal charge the yellow LED starts flashing for a period of 6 months.


    • 6 to 115 kV
    • Solidly grounded neutral
    • 1 wire: Single Wire Earth Return
    • 3 wires (3 phases)
    • 4 wires: 3 phases + Ground wire
    • Bare or covered conductor with external diameter 5-40 mm
    • Steel, concrete or wooden poles
    • Symmetric installation for P-P & P-G detection or asymmetric installation for P-P detection

    Technical characteristics

    Reference / Overall conductor diameter

    FO.LO.CL40.00.WW / 7-28 mm (5-28 mm from mid-2017)
    FO.LO.CL40.30.WW / 17-33 mm
    FO.LO.CL40.40.WW / 24-40 mm


    Сlamp on conductor
    Operating voltage 6-115 kV
    Frequency 45-65 Hz

    Nominal load current

    2-1 000 A
    Min fault current sensing 25 A
    Absolute current threshold 100 А, 250 А, 500 А, 1000 А
    Automatic threshold adjustment (Y/N)
    (differential current threshold)
    50%, 100%, 200% 25 A, 100 A, 200 A, 500 A
    Response time / Inrush resistance / Delay 20 ms / 100 ms
    Indication White LED flashing light
    Fault detected
    Phase to Phase YES
    Phase to Ground
    Fault phase indication YES

    High impedance fault direction indication

    Fault current withstand 25 kA / 500 ms

    Selectable reset time

    6, 12, 24, 48 hours (DIP switches)


    Timer (automatic)
    Magnet (manual)
    Reenergized line (automatic)
    Test Magnet
    Live line installation YES
    Total indicating time
    > 1000 hrs
    Battery life at +40°C 10 years
    Battery Non-rechargeable
    Thionyl Chloride Lithium Battery

    Flashing frequency during indication

    12 times/min
    Protection class IP66
    Standarts / Tests IEC 60068-2-9, IEC 61000-6-2
    IEC 60068-2-30, IEC 60529
    IEC 60068-2-14, IEC 60068-2-11
    IEEE 495 (4.4.7, 4.4.8), IEC 60068-2-6
    IEC 60068-2-29


    0.4 kg

    Service conditions

    Ambient temperature
    -40 ° to +85° C
    Relative humidity 10-100%
    Max altitude 3000 m
    Wind load & pressure 40 m/s (144 km/h)
    200 kg/m2