Bridgeport Fittings Steel Vibr...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$3.46
Bridgeport Vibration and Bonding Locknuts

Bridgeport Fittings Steel Vibration-Resistant Conduit Locknuts with Zinc Plating

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Model: 121-S

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

$3.46
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Bridgeport Fittings Steel Vibration-Resistant Conduit Locknuts with Zinc Plating

Professional conduit fastening solution for harsh vibration environments

Bridgeport Fittings Steel Vibration-Resistant Conduit Locknuts deliver reliable performance in demanding applications where standard locknuts may fail. Engineered with zinc-plated steel construction, these professional-grade locknuts provide secure conduit-to-enclosure connections in harsh vibration environments while offering enhanced corrosion resistance for long-term durability.

Professional Features & Benefits

  • Vibration-Resistant Design: Engineered to maintain secure connections in harsh vibration environments, preventing loosening and maintaining electrical continuity.
  • Zinc-Plated Steel Construction: Steel body with zinc electroplating provides superior durability and long-term corrosion resistance in challenging conditions.
  • Secure Conduit Connection: Fastens threaded conduit to unthreaded openings in boxes and enclosures, ensuring reliable mechanical and electrical connections.
  • UL Listed Quality: UL File E20412 certification ensures compliance with safety standards and professional installation requirements.
  • Harsh Environment Performance: Zinc plating protects against corrosion while steel construction withstands mechanical stress and vibration.
  • Professional Installation: Designed for use in electrical applications requiring secure conduit fastening in demanding environments.

Technical Specifications

  • Country Of Origin: China
  • Department: Electrical
  • Division: Electrical H1
  • Field Application: Used in harsh vibration environments to fasten threaded conduit to unthreaded opening in a box or e
  • Product Finish: Zinc electro-plate
  • Product Material: Steel
  • Secure Connection: The steel conduit locknut fastens the connection from the conduit to the enclosure
  • Sub Division: Electrical-E H2
  • Ul File: E20412
  • Vibration Resistant: Operators can rest easy knowing that the locknut will stay in place in a harsh vibration environmen
  • Zinc Plated Steel Body: The steel body is zinc plated for long-term use in corrosive environments

Professional Applications

  • Industrial Manufacturing Facilities
  • Commercial HVAC Systems
  • Heavy Equipment Installations
  • Transportation Infrastructure
  • Mining and Construction Equipment
  • Marine and Offshore Applications
  • Vibration-Prone Electrical Installations

Why Choose Bridgeport Fittings Quality?

Bridgeport Fittings delivers professional-grade electrical components engineered for demanding applications. With UL Listed certification and zinc-plated steel construction, these vibration-resistant locknuts provide the reliability and durability that electrical professionals trust for secure conduit connections in challenging environments.

Manufacturer Resources

Product Specs

Department:
Electrical
Division:
Electrical H1
Product Finish:
Zinc electro-plate
Product Material:
Steel
Sub Division:
Electrical-E H2
Certifications:
E20412
Product Type:
Locknut
Product Subgroup:
Conduit Fittings
Product Group:
Conduit & Raceway

Bridgeport Fittings 121-S – Frequently Asked Questions

1) What trade sizes do the Bridgeport vibration-resistant steel locknuts come in?
Nine trade sizes, from 1/2 inch up to 4 inch: 1/2 (121-S), 3/4 (122-S), 1 (123-S), 1-1/4 (124-S), 1-1/2 (125-S), 2 (126-S), 2-1/2 (127-S), 3 (128-S) and 4 inch (130-S). Order by the conduit trade size, not the measured outside diameter of the pipe.
2) Will a standard locknut work on a vibrating machine, or do I need the vibration-resistant type?
On equipment that shakes, a plain locknut can back off over time and you lose both the mechanical grip and the bond path. The Bridgeport 121-S series is built for exactly that case: it is made to stay put in harsh vibration environments, fastening threaded conduit to an unthreaded opening in a box or enclosure. Typical use is manufacturing equipment, HVAC machinery, heavy equipment, and transportation infrastructure.
3) Are these Bridgeport steel locknuts UL Listed?
Yes, they are UL Listed under file E20412. That is the number an inspector or a spec reviewer will want on an industrial or institutional job.
4) Can these locknuts be used outdoors or in a damp, corrosive area?
The body is steel with a zinc electro-plate finish, which is there for long-term service in corrosive conditions. Bridgeport lists marine and offshore work among the applications. Steel with zinc plating is a step up from plain steel for exposure, but it is still a plated ferrous part, so in continuously wet or chemically aggressive locations pair it with the appropriate raintight or sealing fittings for that environment.
5) Do these work with rigid and IMC conduit, or only EMT connectors?
These are threaded conduit locknuts, so they thread onto any male conduit thread of the matching trade size, which covers rigid and IMC nipples as well as the threaded ends of EMT connectors and hubs. The job of the nut is to clamp that threaded shank through an unthreaded knockout in a box or enclosure.
6) Is one locknut enough, or do I need two per connection?
One nut on the inside of the enclosure is enough when the fitting has an integral shoulder that seats on the outside face. Where the connection is a threaded nipple or conduit passing through a knockout with nothing to bear against, run a nut on each side of the sheet metal so the nut tightens against the wall. These are sold as individual nuts by trade size, so count accordingly, one for a connector landing and two for a nipple.
7) Does this locknut give me a bonding connection, or do I still need a bonding bushing?
The nut's serrations bite the enclosure metal to make the mechanical and electrical connection from the conduit to the box, which is what maintains continuity. It is not a substitute for a listed bonding bushing or a grounding wedge where the installation calls for one, such as service-entrance raceways or where an equipment grounding conductor has to be terminated at the enclosure.
8) I am standardizing conduit hardware across a plant. Can I use one part family for everything from 1/2 inch branch runs to 4 inch feeders?
Yes. The vibration-resistant steel locknut runs the full range from 1/2 inch to 4 inch in the same zinc-plated steel construction under the same UL file, E20412, so a facility can carry one family and just stock the sizes. The part numbers follow a simple pattern, 121-S through 128-S, with 130-S for the 4 inch.
9) Where is the Bridgeport 121-S series locknut made?
Country of origin is China. Worth knowing up front if you are bidding public work with domestic-sourcing requirements on the material list.
How fast can I get the Bridgeport Fittings 121-S 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 Bridgeport Fittings 121-S come with a warranty?
Absolutely. The Bridgeport Fittings 121-S 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 Bridgeport Fittings 121-S?
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 Bridgeport Fittings 121-S from ZenSupply?
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