Blown Fuse Indicators

The Trigger Indicator (TI) is available on many blade type fuses, primarily Form 101 semiconductor fuses and some Class L fuses. The TI allows blown fuses to be identified visually, eliminating the need for resistance or continuity testing.

It is a field-mountable blown-fuse indicator that is wired in parallel with the fuse to be monitored. The striker pin exerts a static force of one pound and may be used to actuate a switch. It is available in 130, 600, and 1500-volt ratings. The 600V version is a UL Listed accessory. The Trigger Indicator is not a fuse though and should only be used in parallel with fuses rated 70A or higher. To mount the Trigger Indicator, use two midget fuse clips (for 13/32" diameter fuses) found in the Fuse Clip section.


  • Visual Indication or Remote Signaling
  • Optional Auxiliary Microswitches
  • Same Size for All Fuses
  • Retains Optimum Performance
  • Operation at All Times Above 0.9 Volts
  • Low Voltage Design
  • Center Location
  • Rugged Construction
  • Proven Reliability
  • AC or DC
  • UL Recognized


  • Any circuit where visual or relay indication is required


  • Ferraz Shawmut

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