Ag Manufacturing 312 Knockout Seal 1 Inch 3-piece Steel

Product Description

The AG MANUFACTURING 312 is a 3-piece knockout seal with a screw back strap, designed to close and secure unused knockout openings in electrical enclosures, junction boxes, and panel boxes. Constructed from stamped steel, this seal provides a solid, code-compliant closure for 1-inch knockouts. It is typically installed by licensed electricians during rough-in or finish electrical work wherever an open knockout needs to be sealed against dust, debris, and accidental contact with energized components.

This knockout seal is suited for residential and light commercial electrical installations. Common applications include sealing unused openings in breaker panels, junction boxes, conduit bodies, and metal enclosures. The screw back strap design allows for secure, tool-assisted installation without requiring a separate locknut in most applications. The 3-piece kit includes the seal, back strap, and fastening screw for a self-contained installation.

Key Features

• Fits 1-inch knockout openings in standard electrical enclosures
• 3-piece assembly includes seal, screw back strap, and fastener
• Stamped steel construction for durability and code compliance
• Screw back strap secures from the rear of the panel wall without a separate locknut
• Closes unused knockouts to meet NEC enclosure integrity requirements

Compatibility

Designed as an OEM-style replacement and standard-fit knockout seal for 1-inch openings in residential and commercial electrical enclosures, junction boxes, and load centers.

Installation Notes

Installation is performed by a licensed electrician. De-energize and lock out the panel or enclosure before beginning work, in accordance with NFPA 70 (NEC) lockout/tagout requirements. Insert the seal into the knockout opening, position the back strap on the interior side, and tighten the screw to clamp the assembly securely against the enclosure wall. Do not install in energized equipment.

Technical Specifications

• Knockout Size: 1 inch
• Pieces per Set: 3
• Material: Stamped Steel
• Strap Type: Screw Back Strap

Standard Information

• Brand: AG MANUFACTURING
• Manufacturer Part Number: 312