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RACO 187 4 in. Square Steel Box Extender, 1-1/2 in. Deep, with Multiple KO's for Switch Boxes
The RACO 187 is a 4 in. square steel box extender engineered to add usable depth to existing switch boxes and junction boxes within conduit wiring systems. Built with a drawn steel body and no mounting bracket, this extender measures 1-1/2 in. deep and includes multiple knockouts — 1/2 in. and 3/4 in. — to accommodate flexible conduit entry from multiple directions. The square shape matches standard 4 in. switch box dimensions for a clean, secure fit, and the RACO 187 is UL Listed for reliable performance across commercial and residential electrical installations.
Key Features
- Trade Size: 4 in. square extender adds 1-1/2 in. of usable depth to existing switch and junction boxes.
- Durable Steel Construction: Fabricated from drawn steel for strength and long-term durability in conduit installations.
- Drawn Fabrication: Drawn, not welded, construction provides a smooth, seamless box body.
- Multiple Knockouts: Includes 1/2 in. and 3/4 in. knockouts for flexible conduit entry from multiple directions.
- No Bracket Design: Ships without a mounting bracket for direct box-to-box surface mounting.
- Conduit Wiring System: Engineered specifically for conduit wiring system installations.
- Square Profile: 4 in. square shape matches standard switch box dimensions for a clean, aligned fit.
Certifications & Compliance
- UL Listed
Technical Specifications
- Product Type: Steel Box
- Product Size: 4 in
- Product Depth: 1.5 in
- Product Shape: Square
- Drawn or Welded: Drawn
- Bracket Type: No Bracket
- Wiring System: Conduit
- Knockouts: 1/2 in;3/4 in
- Certified Listed: UL Listed
Typical Applications
- Switch Box Depth Extensions
- Junction Box Modifications
- Conduit Wiring Systems
- Commercial and Residential Electrical Installations
- Renovation and Retrofit Wiring Projects
Why RACO?
RACO steel boxes and box extenders are engineered for durable, code-compliant performance on demanding job sites. The drawn steel construction of the 187 extender delivers a rigid, seamless body, while the UL Listing provides added assurance for professional electrical work. With multiple knockouts and a square profile built to match standard switch box dimensions, the RACO 187 offers a practical, dependable solution for extending box depth in conduit wiring systems.
Manufacturer Resources
Spec Sheet
Product Specs
- list_batch:
- RACO-20260916
- Product Type:
- Switch Box
- Product Size:
- 4 in
- Product Depth:
- 1.5 in
- Product Shape:
- Square
- Drawn or Welded:
- Drawn
- Bracket Type:
- No Bracket
- Wiring System:
- Conduit
- Knockouts:
- 1/2 in;3/4 in
- Certified Listed:
- UL Listed
- Department:
- Electrical
- Product Subgroup:
- Electrical Boxes
- Product Group:
- Boxes & Enclosures
RACO RACO187 – Frequently Asked Questions
1) Will the RACO 187 box extender fit a standard 4 inch square steel box?
Yes. The RACO 187 is a 4 inch square extender, so it lines up with standard 4 in. square switch and junction box dimensions for a flush box-to-box fit. It adds 1-1/2 in. of depth on top of the existing box.
2) How much extra depth does the RACO 187 extender add for crowded wire fill?
1-1/2 in. of added depth. That is what you gain in usable box volume when a device box is too shallow for the conductors and device already in it, common on retrofit work where wall build-up pushed the box below the finished surface.
3) What size conduit knockouts are on the RACO 187 extender?
It has both 1/2 in. and 3/4 in. knockouts, on multiple sides, so you can bring flexible or rigid conduit in from more than one direction without adding a separate pull point.
4) Is the RACO 187 extender UL Listed for commercial work?
Yes, it is UL Listed, which is what most commercial and institutional inspectors want to see on a steel box or extender ring going into a conduit system.
5) Does the RACO 187 come with a mounting bracket?
No bracket. The 187 ships bracketless, since it mounts directly onto the existing box rather than to a stud. If you need a stud-mount box with an integral bracket, that is a different item.
6) Is the RACO 187 extender suitable for NM cable (Romex) or only conduit?
It is built for conduit wiring systems. The knockouts are sized 1/2 in. and 3/4 in. for conduit entry, so if you are running nonmetallic sheathed cable you would need cable clamps or connectors rated for that use rather than relying on the box as supplied.
7) Is the RACO 187 welded or drawn steel?
Drawn steel, not welded. A drawn body has no seam to split or corrode at, which is why spec jobs often call it out over welded construction.
8) Where can I get the manufacturer spec sheet for the RACO 187?
Hubbell publishes a spec sheet for the 187 at hubbellcdn.com/specsheet/RACO-187-SPEC-EN.pdf. Order it by manufacturer part number 187.
How fast can I get the RACO RACO187 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 RACO RACO187 come with a warranty?
Absolutely. The RACO RACO187 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 RACO RACO187?
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