Authorized Seco-Larm Reseller

Seco-Larm SD-993B-SS 1,500-lb Electromagnetic Shear Lock, UL Listed

Seco-LarmSKU: SD-993B-SS

Sale price$362.81
Usually ships within 3-5 business days
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Call Us: 718-435-2800


Concealed security for remote access and exit control of aluminum and steel doors or gates. Works with sliding, single-action, and double-action (swing through) doors and gates. Plated steel plugs and magnetic bond holds doors securely in place with approximately 1,500 pounds (680 kg) of shear holding force. Surface-Mount Brackets and U-Brackets also available for surface-mount and glass-door-mount applications.

  • Spring-loaded locking bolts and magnetic bond holds doors securely in place with approximately 1,500 pounds (680kg) of shear holding force
  • No residual magnetism
  • MOV Surge protection
  • Concealed security for remote access and exit control of aluminum and steel doors or gates
  • Smaller size for use with most metal door jambs
  • Zinc-plated magnet and armature, anodized aluminum housing
  • Works with sliding, single-action, and double-action (swing-through) doors and gates
  • Use with an optional digital keypad for keyless high security
  • Easily connects to SECO-LARM’s Electronic Keypads
  • Fail-safe operation (unlocks if power is lost)
  • Armature plate adjusts to compensate for gaps between door and frame
  • Complete mounting hardware for typical installations
  • Additional brackets available for surface mounting or glass-door mounting
  • 12/24VDC Selectable
  • Multiple UL listings
    • UL294 Access Control System Units – USA
    • UL1034 Burglary Resistant Electric Lock – USA


Operating Voltage 12VDC or 24VDC
Current Draw 420mA@12VDC, 210mA@24VDC
Door Gap Max. 1/16″ (2mm)
Holding Force 1,500 lbs. (680 kg.)
Armature Assembly Dimensions (Faceplate) 7-1/8″ x 1-3/16″ x 1-5/8″ (180 x 30 x 42 mm)
Magnet Housing Dimensions (Faceplate) 7-1/8” x 1-3/16” x 1-1/16” (180 x 30 x 27 mm)
Weight 2lbs., 8oz. (1.1kg)



If the shear lock does not activate when the door is closed
  • The magnet assembly is too far away from the armature assembly
  • Adjust the distance between the magnet and armature assembly by adding more shims under the back portion of the armature assembly
  • Re-adjust the position of the armature assembly or the magnet assembly
Poor attraction between the magnet assembly and the armature assembly
  • Check the power supply, and make sure it is according to specifications
  • If the power supply is adequate, replace the unit.
If the magnet assembly pulls the armature assembly, but the door can still be opened
  • Check to make sure the locking bolts are in the armature assembly’s keeper hole when the unit is activated
If the door can be kicked in or pushed in with your shoulder
  • Check to make sure the magnet assembly and armature assembly surfaces are clean and free from dirt
  • Even a little dirt could reduce the attraction between the two surfaces.
For any other problems
  • Test again
  • Replace the unit
  • The problem unit can also be substituted for a working unit in another door frame to see if it works there

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