Thomas & Betts 3940 Blackburn ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$71.63
Thomas & Betts 3940 Blackburn 3/4-Inch Malleable Iron Conduit Hub

Thomas & Betts 3940 Blackburn 3/4-Inch Malleable Iron Conduit Hub

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Model: TB3940

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

$71.63
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Thomas & Betts 3940 Blackburn 3/4-Inch Malleable Iron Conduit Hub

The Thomas & Betts 3940 is a 3/4-Inch malleable iron conduit hub, part of the trusted Blackburn line of electrical connection products from Thomas & Betts. Built to provide a rugged, corrosion-resistant termination point for conduit entering an electrical enclosure, panelboard, or junction box, this hub helps electrical contractors maintain a clean, protected raceway system from source to load. The malleable iron construction offers the strength and durability required for demanding commercial, industrial, and institutional electrical installations, while its 3/4-Inch trade size matches standard 3/4-Inch conduit for straightforward integration into new or existing raceway runs. As a hub-style fitting, the 3940 is designed to seat securely against an enclosure wall, creating a stable mechanical connection that helps protect the conductors routed through the raceway system.

Key Features

  • Trade Size: 3/4-Inch sizing matches standard 3/4-Inch rigid conduit, allowing installation without adapters or reducers in raceway systems built to that size.
  • Durable Malleable Iron Construction: The 3940's malleable iron body resists corrosion and mechanical stress on the jobsite, offering long-term durability along with the ductility needed for a secure, properly seated fit.
  • Conduit Hub Design: As a dedicated hub fitting, the 3940 creates a defined termination point where conduit enters an enclosure or box, helping installers achieve a clean, professional raceway transition and a mechanically sound connection.
  • Enclosure-Ready Fit: The hub is designed to mate with a standard 3/4-Inch enclosure knockout, helping streamline installation at panelboards, boxes, and other equipment housings.
  • Blackburn Product Line: Manufactured under the Blackburn brand by Thomas & Betts, the 3940 carries the reputation of a well-established name in electrical grounding and connection hardware.
  • Field-Ready Design: Sized and constructed for use by electrical contractors, the 3940 is intended to integrate into standard conduit and enclosure installations using typical hand tools.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Conduit-to-Enclosure Connections
  • Panelboard and Junction Box Wiring
  • Commercial and Industrial Electrical Installations
  • Raceway System Terminations
  • New Construction and Retrofit Electrical Work

Why Thomas & Betts?

Thomas & Betts, home to the trusted Blackburn line, builds electrical connection products from rugged malleable iron for lasting performance in professional installations. The 3940 conduit hub reflects that same commitment to durable hardware that electrical contractors rely on for dependable raceway terminations. Choosing a Blackburn fitting from Thomas & Betts means specifying a component built to perform consistently across demanding commercial and industrial jobsites, where reliable conduit-to-enclosure connections are essential to a code-compliant installation.

Manufacturer Resources

Product Specs

list_batch:
TB-20260918
Product Type:
Conduit Hub
Series:
Blackburn
Department:
Electrical
Product Subgroup:
Metallic Conduit
Product Material:
Malleable Iron
Product Size:
3/4"

Blackburn TB3940 – Frequently Asked Questions

1) Will the Thomas & Betts 3940 hub fit a 3/4-inch knockout in my panelboard?
Yes. The 3940 is a 3/4-inch trade size conduit hub built to mate with a standard 3/4-inch enclosure knockout at a panelboard, junction box, or other equipment housing. No reducer or adapter is needed when the knockout and the conduit run are both 3/4-inch.
2) What size conduit does the Blackburn 3940 hub take?
Standard 3/4-inch rigid conduit. The hub is sized to the 3/4-inch trade size, so it drops into a raceway run already built at that size without adapters or reducers. If your run is 1/2-inch or 1-inch, you need the matching hub size instead of this one.
3) Is a malleable iron conduit hub worth it over a die-cast or steel locknut-and-bushing termination?
A hub gives you a single defined termination that seats against the enclosure wall, rather than a locknut-and-bushing stack you assemble on the job. The 3940 body is malleable iron, which brings corrosion resistance plus the ductility to seat properly under torque, which is why it gets specified on commercial and industrial work where the fitting will see mechanical stress. For light interior work in dry locations, a simpler steel connector is usually enough.
4) Can I use the Thomas & Betts 3940 hub for a retrofit on an existing raceway run?
Yes, it is used on both new construction and retrofit electrical work. Because the 3/4-inch sizing matches conduit already in place, it terminates into an existing run at a box or enclosure without reworking the raceway. Installation is done with typical hand tools.
5) Where in a building is the 3940 conduit hub typically used?
Conduit-to-enclosure connections: panelboards, junction boxes, and other equipment housings on commercial, industrial, and institutional electrical installations. It creates the termination point where the conduit enters the box, keeping the raceway closed and the conductors protected from source to load.
How fast can I get the Blackburn TB3940 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 Blackburn TB3940 come with a warranty?
Absolutely. The Blackburn TB3940 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 Blackburn TB3940?
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 Blackburn TB3940 from ZenSupply?
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