Greenlee K3BB 2 1/2" Knockout ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$401.43
Greenlee K3BB 2 1/2" Knockout Plug Seal

Greenlee K3BB 2 1/2" Knockout Plug Seal

(No reviews yet) Write a Review

Model: K3BB

In Stock (leaves warehouse same day if ordered before 3pm ET)

$401.43
Adding to cart… The item has been added
Free Shipping on orders over $199.99
We price match and offer bulk discounts! Click Add to Quote. It's quick and easy.
✨
Earn points with this purchase! You can redeem points for giftcards, iPads, XBox's and more. View Rewards
Free Keying on all locks
You may also like

Greenlee K3BB 2 1/2" Knockout Plug Seal

The Greenlee K3BB is a 2 1/2" knockout plug designed to seal unused knockout openings in electrical enclosures, panelboards, junction boxes, and wireways. Sized to match a standard 2 1/2" knockout, this fitting closes off an opening left after a knockout has been removed but is not being used for conduit entry, helping maintain the integrity of the enclosure. Electricians and contractors rely on properly sized knockout plugs like the K3BB to keep panel and box openings sealed and code-compliant during rough-in and service work.

Key Features

  • Trade Size: Engineered to fit a 2 1/2" knockout opening in electrical panels, boxes, and enclosures.
  • Purpose-Built Fit: Matches standard 2 1/2" knockout dimensions for a secure, snug installation without gaps.
  • Enclosure Sealing: Closes unused knockout openings to help maintain the protective integrity of the enclosure.
  • Simple Installation: Designed for quick placement into the knockout opening during panel or box assembly.
  • Greenlee Reliability: Manufactured by Greenlee, a trusted name in electrical tools and installation hardware for professional trade use.

Technical Specifications

  • Size: 2 1/2"
  • Product Type: Knockout Plug
  • Brand: Greenlee

Typical Applications

  • Sealing Unused Knockouts in Electrical Panels
  • Junction Box and Enclosure Finishing
  • Panelboard and Load Center Assembly
  • Commercial and Industrial Electrical Installations
  • New Construction and Renovation Wiring Projects

Why Greenlee?

Greenlee is a recognized manufacturer of electrical installation tools and hardware relied on by professional electricians. The K3BB knockout plug reflects Greenlee's focus on precision-fit components that help contractors finish panel and enclosure installations cleanly and correctly. Choosing a properly sized Greenlee knockout plug helps keep electrical enclosures sealed and ready for inspection.

Manufacturer Resources

Product Specs

list_batch:
GREE-20260923
Product Type:
Knockout Seal
Department:
Electrical
Product Subgroup:
Enclosure Accessories
Product Size:
1/2"
Product Group:
Boxes & Enclosures

Greenlee K3BB – Frequently Asked Questions

1) What size knockout opening does the Greenlee K3BB plug close?
The K3BB is made for a standard 2-1/2 inch knockout, the opening left by a 2-1/2 inch trade size punch in a panel, junction box, wireway, or load center. It drops into that opening when the knockout has been removed but no conduit is entering there. If your open hole is a different trade size, you need the matching plug for that size instead, since the plug seals by fitting the knockout dimension, not by adjusting.
2) Is a knockout plug required if I punched a hole I ended up not using?
Yes, an unused knockout has to be closed. An open hole breaks the enclosure's protective integrity, and inspectors look for it on panelboards and junction boxes. The K3BB handles the 2-1/2 inch case during rough-in or service work, so you can close out the opening without swapping the whole can.
3) Do I need a tool to install a Greenlee knockout plug, or does it go in by hand?
It is placed into the knockout opening during panel or box assembly, no punch or hole work involved, since the hole already exists. The plug is sized to the knockout so it seats snug without gaps.
4) What is the difference between a knockout plug like the K3BB and a knockout punch?
A punch makes the hole; the plug fills it. Greenlee's K3BB is the plug, used after a 2-1/2 inch knockout has been removed and the opening is not going to carry conduit. If you still need to create the opening in a panel or enclosure, you want a 2-1/2 inch knockout punch and die set, not this part.
5) Can I order the Greenlee K3BB for a commercial panel job, or is it residential only?
Both. The K3BB is used in commercial and industrial electrical installations as well as residential load centers, on new construction and renovation wiring alike. Typical use is sealing unused knockouts in panelboards, junction boxes, enclosures, and wireways.
6) What is the Greenlee part number for the 2-1/2 inch knockout plug?
Order it as Greenlee K3BB. That is the manufacturer part number for the 2-1/2 inch knockout plug seal, which is the identifier to quote when matching a distributor or purchasing record.
How fast can I get the Greenlee K3BB delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Greenlee K3BB come with a warranty?
Absolutely. The Greenlee K3BB is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Greenlee K3BB?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Greenlee K3BB from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
!