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AF0100-00 is an arc-flash relay with a supply voltage of 100–240 VAC and a supply voltage 24–48 VDC.


The AF0100 series arc-flash relay is a cost-effective, microprocessor-based protection relay that limits arc-flash damage by using light sensors to rapidly detect an arc and then trip a circuit breaker. Any combination of point and fiber-optic sensors can be connected to the relay to provide maximum protection. The AF0100 accepts PGA-LS10 point sensors and PGA-LS20/PGA-LS30 fiber-optic sensors. These sensors are designed with a wide detection angle and provide the correct sensitivity for an arc flash. LEDs on the relay and on the sensors indicate sensor health and which sensor(s) detected an arc fault. Sensors, inputs, and trip-coil voltage are monitored to ensure fail-safe operation. A solid-state redundant trip circuit provides an internal fail-safe mechanism and fast arc-flash response during power up.


The AF0100 unit comes with two isolated Form-C contacts for use in applications where multiple devices require tripping. This is especially useful for generator applications where the generator and breaker need to be tripped in case of an arc flash. The relay’s compact size and DIN-rail or surface-mountable features make it ideal for equipment manufacturers.



  • Compact size
  • Works with two different optical sensor types
  • Dual sensor inputs
  • Adjustable light sensitivity
  • Discrete wire networking
  • Fail-safe system
  • USB interface
  • Unit health indication
  • LED indication

Littelfuse Arc Flash Relay AF0100-00


An arc flash is a mass of heat and pressure caused by a switchgear fault. Not only does it cause power outages, but it can also result in loss of business, extensive material damage, and can seriously jeopardize the safety of operational staff. Should a fault occur, arc flash protection minimizes burning time by quickly tripping the circuit breaker, cutting off the current feeding the arc. Short arc burning times are critical, especially when the arc develops during maintenance work on the switchgear, causing property damages. The unique arc fault functionality adds a new dimension to the total protection and reliability of the power distribution installation.


  • Low investment costs and fast installation
    The pre-designed and documented protection schemes are cost-effective, fast to install and commission, and require low investment. One successful operation of the arc protection system provides an immediate return on the investment. 
  • Reduced loss of production
    The faster that arc protection operates, the less damage is caused by the arc fault, reducing the possible outage of the power supply. 
  • Easy installation in existing switchgear
    The product’s design allows for easy installation in existing switchgear. A number of accessories simplify and speed up installation in existing switchgear and electrical panels thanks to its compact design and installation kits. 
  • Reduced insurance costs
    The faster and better the protection system, the more generous the insurance terms and lower the cost should be.   
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