Ag Manufacturing 418 Knockout Seal 3.5 in Stamped Steel 3-piece

Product Description

The AG MANUFACTURING 418 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 durable, code-appropriate closure for 3.5-inch knockouts. The screw back strap design allows for secure, tool-assisted installation without requiring adhesives or specialty fasteners. Electricians and electrical contractors rely on this style of knockout seal to maintain enclosure integrity and meet NEC requirements for closed openings in electrical boxes.

This knockout seal is suited for residential and light commercial electrical installations. It is typically installed in metallic junction boxes, load centers, and other electrical enclosures where a knockout has been removed but the opening is no longer needed. The 3-piece construction with screw back strap allows for easy field installation in both new construction and retrofit service work.

Key Features

• Closes 3.5-inch knockout openings in electrical enclosures and boxes
• Stamped steel construction for durability in standard electrical applications
• 3-piece design with screw back strap for secure, mechanical fastening
• Suitable for maintaining NEC-compliant closed enclosures
• Compact form factor fits standard junction box and panel knockout openings

Compatibility

Designed as an OEM-style replacement and standard-fit knockout seal for 3.5-inch knockout openings in metallic electrical enclosures and junction boxes.

Installation Notes

Installation is typically performed by a licensed electrician. De-energize and lock out the electrical enclosure before installing or servicing any box fittings. Insert the seal body into the knockout opening and tighten the screw back strap to secure it firmly against the enclosure wall. Verify all unused knockouts are properly sealed in accordance with applicable NEC requirements before restoring power.

Technical Specifications

• Knockout Size: 3.5 inches
• Material: Stamped Steel
• Pieces Included: 3
• Fastener Type: Screw Back Strap
• UPC: 780730004188

Standard Information

• Brand: AG MANUFACTURING
• Manufacturer Part Number: 418