HSP-121A Series

The HSP-121A is a UL 1449 Listed, 3 stage Power Line Surge Protector. Features include noise filtering, NEMA 4x enclosure, common mode and normal mode protection. In addition, the HSP12IA can be installed using conduit fittings and can be mounted inside or outside of electronic enclosures.

The HSP-121A offers a replaceable fuse designed to remove the load (protected equipment) from the line if the unit is either overloaded or the internal protection fails. This feature prevents surges from entering equipment through a failed protector, not noticed by the user. Unlike models with only an indicator, which may take weeks to notice, the HSP-121A demands immediate attention upon the unlikely occurrence of internal failure,

Features & Benefits

bullet3-Stage Series Hybrid
bulletPolycarbonate NEMA Enclosure
bullet1/2" or 3/4" Punchouts for nipple conduit connectors
bulletUL 1449 Listed
bulletReplaceable Fuse
bulletFailure Indicator Light
bulletTerminal Screw Connections


 Clamping Cat: 300V L-N, 400V L-G
ANSI/IEEE C62.41 1991-Cat C1/B3  
Peak Clamp Voltage 315V L-N, 350V L-G
Max Single Pulse 10kA
Failure Indication LED
Operational Voltage 120VAC, 60 Hz
Response Time M1ns
Operational Current 15Amps service
Operating Temperature -40o to +85oC
Dimensions (inches) H x W x L 2.95 x 4.95 x 3.00


  1. Mount HSP-121A inside of an electronic rack / enclosure or outside via closed nipple or conduit connections.
  2. Make sure wiring from power sources properly connects to line side of HSP. Wiring from protected equipment must properly connect to EQUIP side of HSP.
  3. Indication of internal failure:
      a. indicator will extinguish
      b. Fuse blown will disconnect load from power source.
    WARNING: For continued protection against risk of fire, replace only with same type rating of fuse.
  4. Connect only to 120 VAC, 15 Amp max., single phase, three wire circuit (L, N, G).

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