Thomas & Betts SBEX Steel City...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$12.28
Thomas & Betts SBEX Steel City Adjustable 1-Gang Switch Box Extension, 3.5 Cu. In. Pre-Galvanized Steel

Thomas & Betts SBEX Steel City Adjustable 1-Gang Switch Box Extension, 3.5 Cu. In. Pre-Galvanized Steel

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Model: TBSBEX

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

$12.28
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Thomas & Betts SBEX Steel City Adjustable 1-Gang Switch Box Extension, 3.5 Cu. In. Pre-Galvanized Steel

The Thomas & Betts SBEX is a Steel City 1-Gang Adjustable Switch Box Extension built in pre-galvanized steel to extend existing single-gang device boxes for switches and receptacles. This adjustable extension ring accommodates up to 7/8-Inch of additional box depth and adds 3.5-Cubic-Inch of usable wiring volume, giving electricians a fast, reliable fix when wall finishes such as tile, paneling, or extra layers of drywall push a device box below the required flush mounting depth. Part of the trusted Steel City product line from Thomas & Betts, the SBEX restores a recessed 1-gang switch or device box to a code-compliant depth without pulling and replacing the entire box, saving both labor and material on renovation and remodel work. It is a purpose-built accessory for electricians who need a dependable way to correct box depth in the field rather than sourcing and installing a brand-new box assembly.

Key Features

  • Adjustable Depth: Extends up to 7/8-Inch, allowing the device box face to be brought flush with the finished wall surface.
  • Durable Construction: Pre-galvanized steel construction resists corrosion and provides long-term durability in standard electrical installations.
  • Single-Gang Design: Sized to match standard 1-gang switch and device box openings for a precise, secure fit.
  • 3.5-Cubic-Inch Capacity: Adds usable wiring volume to help maintain proper box fill as device depth is extended.
  • Steel City Product Line: Manufactured as part of the Steel City line from Thomas & Betts, a recognized name in steel electrical boxes and fittings.
  • Purpose-Built Extension: Designed specifically to extend an existing 1-gang switch box rather than requiring a full box replacement.
  • Renovation-Ready: Ideal for correcting box depth after adding tile, paneling, or additional drywall layers to a finished wall.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Extending Recessed 1-Gang Switch and Device Boxes
  • Renovation and Remodel Electrical Work
  • Correcting Box Depth Behind Tile, Paneling, or Added Drywall
  • Residential and Commercial Wiring Extensions
  • Code-Compliant Box Depth Adjustments

Why Thomas & Betts?

Thomas & Betts backs the Steel City line with pre-galvanized steel construction built for reliable, jobsite-ready performance. The SBEX switch box extension gives electricians a straightforward way to correct box depth issues without the added labor and cost of a full box replacement, reflecting the practical, trade-tested engineering behind the Steel City brand and its 1-gang box accessories. It's a small part that solves a common finishing problem, keeping installations on schedule and up to code.

Manufacturer Resources

Product Specs

list_batch:
TB-20260918
Product Type:
Box Extension Ring
Configuration:
Single Gang
Series:
Steel City
Department:
Electrical
Product Subgroup:
Electrical Boxes
Product Material:
Pre-Galvanized Steel
Product Group:
Boxes & Enclosures
Product Color:
Silver

Steel City TBSBEX – Frequently Asked Questions

1) My switch box ended up recessed behind new tile. Will the Steel City SBEX bring it back flush?
That is exactly what the SBEX is for. It's a 1-gang extension ring that picks up an existing single-gang switch or device box and brings the face forward by up to 7/8 inch, so the device sits flush with the finished wall after tile, paneling, or a second layer of drywall goes on. If your finish added more than 7/8 inch of thickness, one SBEX won't get you all the way there.
2) Does the SBEX extension ring add box fill volume, or do I still have a box fill problem?
It adds 3.5 cubic inches of usable wiring volume on top of whatever your existing 1-gang box provides, so the extension helps rather than hurts your fill calculation. Add that 3.5 cu. in. to the volume stamped in your existing box when you run the count for conductors, devices, and clamps.
3) Will a 1-gang extension ring fit a two-gang box?
No. The SBEX is a single-gang extension, sized to standard 1-gang switch and device box openings. For a two-gang opening you need a 2-gang extension ring; the single-gang ring will not cover or screw to the wider box.
4) Is it better to add an extension ring or just replace the recessed box?
Replacing the box means opening the wall, pulling the old box, and re-terminating. The SBEX avoids all of that: it mounts onto the box that's already there and corrects the depth in place, which is why it's the usual call on remodel and renovation work where the wall is already finished. Replace the box instead when the existing box is damaged, when you need more volume than the extension's 3.5 cu. in. adds, or when the finish buried the box deeper than 7/8 inch.
5) Can I use the SBEX behind a receptacle, or is it only for switches?
Both. It's catalogued as a switch box extension, but it extends any standard 1-gang device box, so receptacles, dimmers, and switches all work. Applications run from residential remodels to commercial wiring extensions.
6) Is the SBEX adjustable, or is it a fixed 7/8-inch depth?
Adjustable. You set it anywhere up to 7/8 inch of added depth, so you can dial the device face to match the actual thickness of the finish you added rather than being locked to one offset.
7) What is the SBEX made of, and will it corrode in a damp interior wall?
Pre-galvanized steel, silver in appearance. The zinc coating gives it corrosion resistance for standard interior electrical installations, the same material family as the rest of the Steel City steel box line. It is not described for wet or outdoor use.
8) What part number do I order for the Thomas & Betts Steel City 1-gang box extension?
Order model SBEX. There's one configuration, no finish or size choices to specify, and it's the single-gang pre-galvanized steel extension ring in the Steel City line.
How fast can I get the Steel City TBSBEX 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 Steel City TBSBEX come with a warranty?
Absolutely. The Steel City TBSBEX 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 Steel City TBSBEX?
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 Steel City TBSBEX from ZenSupply?
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