Thomas & Betts 2531 Strain Relief Cord Connectors-Straight

The 2531 straight strain relief connector clamps cable from 0.250 to 0.375 inch outside diameter (6.35 to 9.525 mm). Measure the jacket OD of the cord, not the conductor gauge. A cord above 3/8 inch will not seat in the grip, and anything under 1/4 inch won't get enough bite from the clamp to hold.

The Bridgeport Fittings RSR-2106 is a straight cord grip connector with a 3/4 inch NPT hub, the same hub size as the Thomas & Betts 2531, which also uses a 3/4 inch NPT thread. The difference to check before you swap is body material and cord range: the 2531 body is zinc die cast and it grips cord from 0.250 to 0.375 inch (6.35 to 9.525 mm) diameter, while the RSR-2106 is an aluminum body. Confirm the cord outside diameter falls in the grip range of whichever one you order.

No. The 2531 is built for cord with an outside diameter of 0.250 to 0.375 inch (6.35 to 9.525 mm), and a larger jacket will not seat in the grip even though the hub is 3/4 inch NPT. The 3/4 inch hub size is shared by other straight cord grips such as the Bridgeport Fittings RSR-2106, so you can keep the same box and conduit prep and step to a connector whose published cord range covers your actual jacket diameter. Measure the jacket, not the conductor count, before ordering.

Yes. The 2531 carries UL file E13938 and CSA certification, and it also meets Coast Guard CG293, which is why it shows up on marine and shipboard work as well as general industrial jobs.

Rated to 105 degrees C, with an operating range of 0 to +105 degrees C. That covers most motor terminal boxes, lighting, and process equipment feeds. For sub-freezing outdoor or cold-storage installs, the stated range starts at 0 C, so it's not a cold-room part.

Zinc die cast, metallic finish, in its natural uncoated colour. Metal body means it carries bonding through the threaded hub when installed with a proper locknut, and it holds up to mechanical abuse better than a nylon gland on exposed equipment.

It's a true strain relief fitting, not just a bushing. The clamp grips the cord jacket so pulling load is taken by the connector body and the box, not by the conductor terminations inside. That's the required arrangement any time a flexible cord enters a box or piece of equipment.

For marine work, the Thomas & Betts 2531 is the one to specify: it is a zinc die cast straight cord connector that meets Coast Guard CG293 and carries UL E13938 and CSA. The comparable Bridgeport Fittings RSR-2106 is an aluminum-bodied 3/4 inch NPT cord grip connector. Both are straight-hub cord grips, so the decision comes down to the body metal suiting your environment and, in a marine panel, the CG293 call-out on the 2531.

Not without changing how the cord leaves the enclosure. The 2531 is a straight cord connector, so the cord exits in line with the 3/4 inch NPT hub; an angled body redirects the cord and needs different clearance behind the box. The comparable Bridgeport Fittings RSR-2106 is also a straight-body cord grip connector, so it preserves the same straight exit path. If you need the cord turned, that is a different fitting style, not a drop-in for the 2531.

Only if the gland is rated to provide strain relief. The 2531 is a strain relief cord connector, meaning it clamps the cord jacket so pull is taken off the terminations, and it is rated to 105 degrees C. A sealing-only gland passes the cord through without that mechanical hold. Among straight 3/4 inch NPT alternatives, the Bridgeport Fittings RSR-2106 is also a cord grip connector rather than a pass-through bushing. For equipment cords that get flexed or tugged, specify the strain relief style.

They come 10 to an inner carton and 100 per outer carton, with the outer running about 19 lbs per 100 pieces. Useful if you're standardizing a panel shop or a repetitive equipment hookup and want to order full cartons.