D0920 Series – Arc-Detection Unit Series - Littelfuse D0920 Arc-Detection Units Offer Superior Arc-Fault Detection

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Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities.

The D0920 series arc-detection unit is a high-speed relay used for electrical power-distribution systems. It provides a simple and cost-effective solution for arc-flash monitoring. This device supports up to two A0220 point sensors mounted in a switchboard and requires a 230 V ac supply. The D0920 detects a fault and pulses the trip output in less than 1 ms. The fast trip time reduces the risk of personal injury and equipment damage. The A0220 features a 180° detection zone and can detect an arc as small as 3 kA within a 2 m half-sphere. These point sensors are available with 10 m cabling. The D0920 arc-detection unit provides superior protection against the damaging effects of arc flashes and improves the lifespan of electrical equipment as well as the protection of personnel. This unit holds both CCC and CE certifications.


The D0920 is typically supplied from the switchboard main power. The ac voltage may fail when an arc fault develops. The D0920 uses energy stored in an internal capacitor to trip the circuit breaker. The storage capacitor is an extremely long-life electrolytic capacitor with a specified lifetime of more than 30 years at an ambient temperature of 50 °C (121 °F). The trip energy stored is sufficient for circuit breakers with a 220/250 V dc shunt trip coil. The D0920 has one output indication relay with an isolated, normally-open contact, and one output indication relay with an isolated, normally-closed contact. Additional features include power and trip indication, test mode, and sensitivity adjustment.


  • Compact size
  • Trip time <1 ms
  • Flexible certification
  • Sensor input handles one or two sensors
  • Adjustable light sensitivity
  • Test mode

Access specifications, certifications, check availability and order parts below

Catalog #Weight (lbs/g)StockSamples
D0920.00600.48 KgCheckOrder

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Catalog # Certificates
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D0920.0060 CCCicon
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