AF0500- Littelfuse Arc Flash Relay

The AF0500- Littelfuse Arc Flash Relay is mainly used to detect arc faults in electrical systems and protect equipment and personnel in electrical systems from arc faults. Arc protection relays can detect arcs by monitoring parameters such as current, voltage, and electric power, and quickly disconnect the power supply before an electrical fire occurs, thereby reducing the risk of fire.


Arc protection relays are usually used in medium and high-voltage power distribution systems, control cabinets, transformers, generators, motors and other electrical equipment. They adopt the dual-criteria principle of arc light detection and overcurrent detection and have the characteristics of fast protection action and high reliability.

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  • Continuous system self-supervision
  • Event logs, disturbance recording and real-time clock
  • Three-phase current, Zero-sequence current
  • Two change-over alarm contacts including IF
  • Complete digital design, simple principle;
  • Strong electrical performance;
  • Comprehensive record of fault information;
  • Double criterion of over-current and arc, high reliability;
  • Optical fiber transmits, strong electromagnetic interference resistance;
  • Programmable logic of trip exit;
  • Fast exit tripping, short total fault clearing time.



  • Reduce the harm of arc light to human body;
  • Reduce damage to equipment caused by arc short-circuit faults;
  • Avoid transformer damage caused by bus failure;
  • Protect the dc system in the station;
  • Ensure the stable operation of power substations;
  • Thermal power plant electrical section switchgear;
  • Wind farm and photovoltaic station switchgear;
  • Large municipal engineering project;



Power Supply Universal 100 to 240 Vac (+10%, -15%) 50/60 Hz, 20 VA,

110 to 250 Vdc (+10%, -20%) 8 W

Low Voltage 24 to 48 Vdc (+10%, -20%), 4 W
Sensor Inputs 4 light sensor inputs for PGA-LS10,

PGA-LS20 and PGA-LS30 sensors

Voltage Rating 24 to 300 Vac, 24 to 300 Vdc
Current Rating 20 A for 2 s, 10 A for 5 s
Make/Carry 30 A for 0.2s
Trip Outputs  2 IGBT switches UL Rating      120/240 Vac,

1800 VA, 0.75 A maximum continuous,

125/250 Vdc, 138 VA, 0.75 A maximum continuous

Communication Ethernet, 2 ports with internal Ethernet switch,

Modbus® TCP

Mounting      Surface DIN (with optional D0050 adapter clips)
Approvals UL Listed (UL508), CE, RCM, FCC, CSA
Operating Temp. –40°C to +70°C
Dimensions H 130 mm (5.1”); W 200 mm (7.9”); D 54 mm (2.1”)
Shipping Weight 0.9 kg (2 lb)