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Black industrial watertight locking plug, straight orientation, five blades, thermoplastic elastomer housing, screw terminals

Hubbell Incorporated

Hubbell Incorporated HBL26W81BK Watertight Locking Plug L21-20P 20 A 120/208V AC

SKU CH-V2Y4-9CKM8

Watertight industrial locking plug with NEMA L21-20P configuration rated for 20 A at 120/208V AC three-phase power

  • TypeWiring Devices
  • Watertight seal protects connections in wet environments
  • NEMA L21-20P locking design prevents accidental disconnection
  • Chemical and impact resistant thermoplastic elastomer housing
  • Screw terminals accept 0.375 to 0.875 inch cable diameters
  • 20 A three-phase 120/208V AC rating for industrial power

Watertight Locking Plug L21-20P

This industrial-grade locking plug provides a secure, watertight connection for three-phase equipment. Rated at 20 A and 120/208V AC, it features a straight orientation and screw-terminal wiring. The thermoplastic elastomer housing resists chemicals and impact. It accepts cable diameters from .375 in to .875 in.

Suited for three-phase industrial power

Electricians and maintenance teams use this plug on machinery, generators and temporary power distribution where a 4-pole, 5-blade NEMA L21-20P connection is specified. The polarized, locking design prevents accidental disconnection in wet or high-vibration environments. It is not for single-phase loads, different voltage ratings or non-locking receptacles.

NEMA L21-20P configuration decides fit

The plug only mates with a matching NEMA L21-20R receptacle carrying 4 poles and 5 blades at 120/208V AC three-phase. Verify the receptacle rating and wiring scheme before installation. Cable outside diameter must fall between .375 in and .875 in for the gland seal to remain watertight.

Highlights

  • Watertight seal protects connections in wet environments
  • NEMA L21-20P locking design prevents accidental disconnection
  • Chemical and impact resistant thermoplastic elastomer housing
  • Screw terminals accept 0.375 to 0.875 inch cable diameters
  • 20 A three-phase 120/208V AC rating for industrial power

Specifications

BrandHUBBELL WIRING DEVICE-KELLEMS
TypeWiring Devices

Questions about this item

What cable diameter range does the HBL26W81BK plug accept?

The plug accepts cables from 0.375 in to 0.875 in diameter, covering the stated minimum and maximum for the thermoplastic elastomer housing.

How is the L21-20P plug wired, and which step is often missed?

Strip conductors to the terminal depth, insert each into its marked screw terminal, tighten to secure all five blades, then assemble the watertight housing — many forget to seat the gasket before final tightening.

Which parts of the HBL26W81BK will need inspection or replacement over time?

Check the screw terminals for corrosion, the gasket for compression set, and the thermoplastic elastomer housing for chemical or impact damage; replace the plug if any component shows degradation.

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