Crouse-Hinds TP422 4" Steel Sw...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$6.68
Crouse-Hinds TP422 4-inch steel switch box extension ring, 1-1/2 inch deep, welded construction, galvanized finish, angled view showing knockout openings and mounting holes

Crouse-Hinds TP422 4" Steel Switch Box Extension Ring 1-1/2" Deep

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Model: TP422

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

$6.68
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Crouse-Hinds TP422 — 4" Steel Switch Box Extension Ring, 1-1/2" Deep

⚠ Compatibility Note: This extension ring is designed for use with switch boxes only — it is not compatible with 4-square boxes. Verify your existing box type before ordering.

The Crouse-Hinds TP422 extends a standard 4" switch box by 1-1/2", adding 21 cubic inches of capacity for wire connections and device installations in ordinary/non-hazardous locations. Welded steel construction provides structural integrity for demanding residential, commercial, and renovation applications.

Key Features

  • 21 Cubic Inch Capacity: Ample space for wire connections and electrical components
  • Welded Steel Construction: Structural integrity and long-term durability
  • 1-1/2" Extension Depth: Adds necessary depth for proper wire management and device clearance
  • Multiple Knockout Options: (8) 1/2", (4) 1/2", and (1) 3/4" knockouts for versatile conduit entry
  • NEC/CEC Compliant: Meets code requirements for safe, compliant installations

Technical Specifications

  • Model: TP422
  • Box Size: 4"
  • Depth: 1-1/2" (1.5 in)
  • Width: 4 in
  • Length/Depth: 4 in
  • Capacity: 21 cubic in
  • Construction: Welded Steel
  • Weight: 0.5 lb
  • Side Knockouts: (8) 1/2 in, (4) 1/2 in, (1) 3/4 in E
  • Area Classification: Ordinary/Non-Hazardous Locations
  • Standards: NEC/CEC

Typical Applications

  • Residential wiring where additional box depth is required
  • Commercial and light industrial electrical installations
  • Renovation and remodel projects with existing switch box constraints
  • Multi-unit residential and property management maintenance

Manufacturer Resources

Product Specs

Area Classification:
Ordinary/Non-Hazardous Locations
Box Size:
4"
Capacity:
21 cubic in
Construction:
Welded
Product Details:
For use as extension with switch box, not 4 square box
Product Height:
1.5 in
Product Length Depth:
4 in
Product Material:
Steel
Product Weight:
.5 lb
Product Width:
4 in
Side Knockouts:
(8) 1/2 in, (4) 1/2 in, (1) 3/4 in E
Standards Type:
NEC/CEC
Product Depth:
1-1/2"
Department:
Electrical
Product Type:
Switch Box
Product Subgroup:
Electrical Boxes
Product Group:
Boxes & Enclosures

Crouse-Hinds TP422 – Frequently Asked Questions

1) Will the Crouse-Hinds TP422 extension ring fit a 4-inch square box?
No. The TP422 is built as an extension for a 4 inch switch box, not a 4-square box. If the box in the wall is a 4-11/16 or 4 inch square box, this ring will not land on the mounting ears correctly and you need a square-box extension ring instead. Check the box body before ordering, since the two styles look similar once the plaster ring is off.
2) How much box fill does a TP422 extension ring add?
It adds 21 cubic inches of usable volume at 1-1/2 inches of added depth. That is the number to carry into an NEC box fill calculation when an existing switch box is over-crowded, and in practice it is what lets a stuffed box take a dimmer, a smart switch, or an extra pair of conductors without a full box replacement.
3) My switch box is set too deep behind the drywall. Will an extension ring fix that?
That is the main job for this part. The TP422 adds 1-1/2 inches, bringing the device plane forward to a flush wall surface where a box got recessed behind added drywall, tile, or panelling. If the box is set back more than 1-1/2 inches you will need a deeper extension; if it is set back less, you still use this ring, since it is a single fixed depth with no adjustment.
4) What size conduit knockouts are on the Crouse-Hinds TP422?
The ring carries (8) 1/2 inch, (4) 1/2 inch, and (1) 3/4 inch knockouts around the sides, so you can bring EMT or flex in at the extension itself rather than reopening the original box. The single 3/4 inch opening is the one to plan for if a larger raceway or a cable connector needs to land here.
5) Is the TP422 extension ring rated for a hazardous location?
No. It is classified for ordinary, non-hazardous locations only. For a Class I or Class II area you need explosion-proof enclosure components, not a standard steel extension ring. For normal residential, commercial, and light industrial interiors it is the right part.
6) Can I use an extension ring instead of replacing an overfilled switch box?
Yes, and it is usually the faster call on occupied units. Cutting out and re-setting a box means patching drywall and paint; the TP422 bolts to the existing 4 inch switch box, adds 21 cubic inches, and the device and coverplate mount to the ring. For property managers standardizing across a building, ordering one part number, TP422, covers every switch box that came up short.
7) What are the outside dimensions of the Crouse-Hinds TP422?
Measures 4 x 4 x 1.5 inches. That footprint matters on a remodel where the ring has to sit inside a cut opening or clear a stud, corner bead, or an adjacent box, because the extension is the same 4 inch face as the switch box behind it and gains nothing in width.
8) Does the TP422 meet NEC and CEC requirements?
It is built to NEC/CEC standards for ordinary location wiring. The practical point for an inspector is box fill: the 21 cubic inch rating is what you add to the existing box volume when you show the conductor and device count works out.
How fast can I get the Crouse-Hinds TP422 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 Crouse-Hinds TP422 come with a warranty?
Absolutely. The Crouse-Hinds TP422 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 Crouse-Hinds TP422?
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 Crouse-Hinds TP422 from ZenSupply?
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