Mulberry 40454 Rubber Telephon...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$0.54
Mulberry 40454 Rubber Telephone Grommet for 1/2-Inch Knockout, 7/8-Inch Hole

Mulberry 40454 Rubber Telephone Grommet for 1/2-Inch Knockout, 7/8-Inch Hole

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Model: 40454

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

$0.54
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Mulberry 40454 Rubber Telephone Grommet for 1/2-Inch Knockout, 7/8-Inch Hole

The Mulberry 40454 Rubber Telephone Grommet is engineered for use with a 1/2-inch knockout, providing a 7/8-inch hole opening for telephone and low-voltage cable pass-through. Molded from durable rubber, this grommet shields cables from sharp metal edges at knockout openings while allowing clean, snag-free routing through electrical panels, boxes, and enclosures. It is a practical, purpose-built accessory for electricians and low-voltage installers working on telephone, data, and communication wiring systems in commercial and residential settings, and it is equally useful for new construction rough-in or retrofit and remodel work where a finished, protected cable opening is required.

Key Features

  • Trade Size: Sized for a 1/2-inch knockout with a 7/8-inch hole opening, matched to standard telephone and low-voltage cable diameters.
  • Durable Rubber Construction: Molded rubber body resists tearing and flexes to seat securely and stay in place within the knockout opening.
  • Edge Protection: Shields cable jacketing from sharp metal edges at panel and enclosure knockouts, reducing the risk of nicks, abrasion, and long-term wear.
  • Telephone Grommet Design: Purpose-built for telephone and low-voltage cable pass-through applications rather than general power wiring.
  • Simple Installation: Fits directly into a prepared 1/2-inch knockout for quick, tool-free placement during rough-in or retrofit work, with no additional hardware required.
  • Space-Efficient Profile: Low-profile design fits flush within the knockout so panels, boxes, and enclosures close and mount without interference.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Telephone and Data Wiring Installations
  • Panel and Enclosure Knockout Protection
  • Low-Voltage Cable Pass-Through
  • Commercial and Residential Wiring Projects
  • Rough-In and Retrofit Electrical Work
  • New Construction and Remodel Applications

Why Mulberry?

Mulberry rubber grommets are built to protect cables at metal knockout openings, giving electricians and low-voltage installers a simple, reliable accessory for clean, professional-grade installations. The molded rubber construction is designed to stay seated in the knockout while shielding cable jacketing from sharp edges, helping installers avoid damaged cables and repeat service calls. Choosing a Mulberry grommet helps ensure telephone and data cabling is shielded from damage at knockout edges, supporting neater, more dependable wiring work across a wide range of commercial and residential projects.

Manufacturer Resources

Mulberry Full Line Catalog

Product Specs

Product Type:
Gland Plate & Entry Seal
Department:
Electrical
Product Group:
Boxes & Enclosures
Product Subgroup:
Enclosure Accessories

Mulberry 40454 – Frequently Asked Questions

1) Will the Mulberry 40454 grommet fit a standard 1/2-inch knockout in a panel or junction box?
Yes. The Mulberry 40454 rubber grommet is sized for a 1/2-inch knockout and presents a 7/8-inch hole opening for the cable. A 1/2-inch trade size knockout punches at roughly 7/8 inch in the metal, which is why the grommet seats in it and leaves the full 7/8-inch opening clear for the cable to pass. It drops in by hand, no locknut or additional hardware.
2) Can I use a telephone grommet like the Mulberry 40454 for power wiring instead of a connector?
No. The 40454 is a telephone grommet, built for telephone, data, and other low-voltage cable pass-through, not general power wiring. For line-voltage conductors entering a box or panel you need a listed cable or conduit connector appropriate to the wiring method. Use the grommet where you are routing communication cable through a knockout and want the jacket protected from the cut metal edge.
3) What does a rubber grommet actually do at a knockout opening that leaving the hole bare does not?
A punched knockout leaves a sharp metal edge. Pull Cat cable or station wire across it and the jacket nicks, then abrades over time as the cable moves. The molded rubber body of the 40454 lines that edge so the cable rides on rubber instead of steel, which is what keeps a low-voltage run from failing months after the install.
4) What is the exact part number to order for the Mulberry 7/8-inch telephone grommet?
Order Mulberry part number 40454. That is the rubber telephone grommet for a 1/2-inch knockout with a 7/8-inch hole opening, and it is a single model with no finish or size options to specify.
5) Will the grommet stick out and keep an enclosure cover from closing?
No. The 40454 has a low-profile body that seats flush within the knockout, so panel covers, box fronts, and enclosure doors close and mount without the grommet fouling them.
6) Is the Mulberry 40454 suitable for retrofit work in existing boxes, or only new rough-in?
Both. Because it presses into an already-prepared 1/2-inch knockout with no tools or fasteners, the 40454 works for new construction rough-in and for remodel or retrofit work where an open knockout needs a finished, protected cable opening.
How fast can I get the Mulberry 40454 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 Mulberry 40454 come with a warranty?
Absolutely. The Mulberry 40454 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 Mulberry 40454?
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 Mulberry 40454 from ZenSupply?
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