Thomas & Betts 3211 One-Piece ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$1.80
Thomas & Betts 3211 One-Piece Knockout Bushing, 1.109" Plastic

Thomas & Betts 3211 One-Piece Knockout Bushing, 1.109" Plastic

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Model: TB3211

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

$1.80
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Thomas & Betts 3211 One-Piece Knockout Bushing, 1.109" Plastic

The Thomas & Betts 3211 is a one-piece, non-metallic knockout bushing engineered to protect conductor insulation as wires and cables pass through knockout openings in electrical enclosures, panelboards, junction boxes, and cabinets. Molded from durable plastic in a single-piece design, this 1.109" bushing snaps securely into matching knockout openings without a separate locknut or additional hardware, providing a smooth, rounded internal edge that shields cable jacketing and wire insulation from abrasion, cutting, or chafing. Its non-metallic construction makes the 3211 a lightweight, corrosion-resistant, non-conductive alternative to traditional metal locknut-and-bushing assemblies, well suited for standard electrical wiring applications where a fast, hardware-free knockout closure is preferred. The 3211 is commonly specified as a direct-fit replacement for standard 1.109" knockout openings found in panelboards, meter enclosures, and junction boxes across residential, commercial, and industrial wiring projects.

Key Features

  • Trade Size: 1.109" bushing diameter sized to fit matching knockout openings in enclosures, panelboards, and boxes.
  • Durable Construction: Molded non-metallic plastic resists corrosion and will not conduct electricity, unlike traditional metal bushings.
  • One-Piece Design: Single-piece molded body installs in one step with no separate locknut or hardware required.
  • Knockout Protection: Smooth internal bore shields wire and cable insulation from sharp knockout edges during and after installation.
  • Tool-Free Installation: Snaps into the knockout opening from inside the enclosure for a quick, secure fit without wrenches or additional fasteners.
  • Non-Conductive Material: Plastic construction provides electrical insulation at the knockout opening, adding a layer of protection beyond bare metal edges.
  • Lightweight Profile: Non-metallic plastic construction reduces overall enclosure weight compared to steel or malleable iron bushings.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Electrical Panelboards and Enclosures
  • Conduit and Raceway Knockout Openings
  • Meter Enclosures and Junction Boxes
  • Commercial and Industrial Electrical Installations
  • Residential and Light Commercial Wiring
  • New Construction and Renovation Wiring Projects

Why Thomas & Betts?

Thomas & Betts has long supplied electrical contractors and panel builders with dependable conduit and enclosure hardware, and the 3211 knockout bushing continues that tradition with a one-piece, non-metallic plastic body designed for straightforward installation and long-term durability. This hardware-free, single-piece design helps electricians protect wiring insulation, reduce installation time, and maintain clean, professional enclosure openings. Choose the Thomas & Betts 3211 when you need a dependable, corrosion-resistant, non-conductive bushing solution sized to fit 1.109" knockout openings in panelboards, boxes, and cabinets.

Manufacturer Resources

Product Specs

list_batch:
TB-20260918
Product Type:
Conduit Bushing
Configuration:
One-Piece
Department:
Electrical
Product Subgroup:
Conduit Fittings
Product Material:
Plastic
Product Size:
1.109"
Product Group:
Conduit & Raceway
Product Color:
Black

Thomas & Betts TB3211 – Frequently Asked Questions

1) Does the 3211 knockout bushing need a locknut or any other hardware?
No. It's a one-piece molded body that snaps into the knockout from inside the enclosure, so there is no separate locknut, washer, or fastener to buy. No wrench or tool needed either, which is the main reason panel builders use it instead of a metal locknut-and-bushing pair.
2) Can a plastic knockout bushing be used instead of a metal one in a panelboard?
The 3211 is molded plastic rather than steel or malleable iron. That makes it non-conductive and corrosion resistant, and it adds no weight to the enclosure. Where you are only closing off a knockout and protecting conductor insulation from the sharp edge, the plastic bushing does that job. Where the fitting has to carry a bonding path or terminate metal conduit, you need a metal bushing or a grounding bushing instead.
3) Will the 3211 protect THHN conductors pulled through a bare knockout edge?
That is what it's for. The bushing presents a smooth, rounded internal bore at the opening so wire insulation and cable jacket aren't cut or chafed by the raw knockout edge during the pull or afterward from vibration. Install it before pulling conductors through.
4) I have a panel with unused 3/4 inch knockouts. Is the 3211 the right part to close them off?
For a knockout you are running a wire or cable through, yes, the 3211 fits the 1.109 inch opening and protects the conductor at the edge. For a knockout with nothing passing through it, you want a knockout seal or closure plug instead, not a bushing, since the bushing leaves an open bore.
5) What is the Thomas & Betts part number and color of this 1.109 inch knockout bushing?
Order it as Thomas & Betts 3211. The molded body is black plastic, which is standard for non-metallic knockout bushings and matches what is typically already in a panel.
6) Can one 3211 bushing be used for several conductors through the same knockout?
Yes, it is a single open bore at the knockout, not a cord grip or connector, so any conductors you pull through that 1.109 inch opening ride on the same rounded edge. It does not clamp or strain-relieve the cable, so if the application needs the cable secured at the enclosure, use a cable connector instead.
How fast can I get the Thomas & Betts TB3211 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 Thomas & Betts TB3211 come with a warranty?
Absolutely. The Thomas & Betts TB3211 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 Thomas & Betts TB3211?
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
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