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Galvanized steel one-gang extension ring with multiple knockouts

Hubbell Incorporated

Hubbell Incorporated RACO 661 Extension Ring 1 Gang Galvanized Steel Electrical Box

SKU CH-MH2K-57P29

A one-gang galvanised steel extension ring with 13 cu in capacity, five half-inch side knockouts and two back knockouts, UL Listed

  • Product typeElectrical Boxes & Covers
  • 1-gang extension ring adds wiring space
  • Galvanized steel resists corrosion in damp locations
  • 13 cu in capacity fits multiple conductors
  • Seven 1/2 in. knockouts allow flexible cable entry
  • UL Listed for code-compliant installations

RACO 661 One-Gang Extension Ring

The RACO 661 is a galvanised steel extension ring designed for one-gang electrical box installations. It adds 13 cubic inches of wiring capacity to an existing box, helping electricians meet fill requirements during remodels or new work. The unit carries a UL listing and is finished in grey for corrosion resistance.

Knock-Out Layout and Mounting

Five half-inch side knockouts and two half-inch back knockouts provide multiple cable entry options for flexible routing. A type A bracket secures the ring to the mounting surface without the need for separate clamps. The pressed steel construction maintains rigidity while allowing standard tool access during installation.

Suited for Shallow Box Extensions

This ring suits projects where a standard one-gang box lacks the depth required by code or device specifications. It is not intended for multi-gang assemblies, larger capacity demands, or environments requiring non-metallic enclosures. Installers needing different knockout configurations or deeper enclosures should evaluate alternative box accessories.

How it compares

Measured against everything we stock in Electrical Enclosures & Cabinets, at today’s prices. Recalculated every night.

Price $2.99
Cheaper than about 95% of the 1,411 comparable items (median $39.99).

Specifications

Product
Brand nameRACO
Product typeElectrical Boxes & Covers

Questions about this item

Will the 13 cu in capacity limit how many wires I can add later?

The 13 cubic-inch capacity sets the maximum fill allowed by code, so any future wiring changes must stay within that volume.

What stops me from mounting more devices on the single-gang frame?

The box is a 1-gang Handy type, so only one device fits; adding more would require a larger multi-gang box.

Does the galvanized steel get hot when the circuit runs all day?

Steel dissipates heat well, and the UL listing confirms safe temperature rise under continuous rated load.

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