Steel City 52-C-21 Square Box Plaster Ring 2 Gang

Product Description

The STEEL CITY 52-C-21 is a raised-type square box plaster ring designed for two-gang device installations on 4-inch square electrical boxes. Fabricated from hot-rolled pre-galvanized AISI C-1008 steel meeting ASTM G90-U at 0.062 inches thick, this ring raises device mounting height by 1-1/4 inches to accommodate finished wall surfaces. It carries a 15 cubic inch capacity rating and holds approvals from UL 514A, CSA, and FS W-J-800. Licensed electricians use this ring during rough-in and finish stages to properly position outlet, switch, or device plates flush with drywall or plaster surfaces.

The 52-C-21 is suited for residential and light commercial wiring projects where 4-inch square boxes are installed in drywall or plaster wall assemblies. The two-gang opening type accommodates standard duplex receptacles, switches, or combination devices side by side. The 1-1/4 inch raise makes it well-matched for typical single-layer drywall applications. It is packaged 25 units per carton, making it practical for tract work, multi-unit residential construction, and service panel rough-ins where consistent device depth is required across multiple boxes.

Key Features

• Quick-release locking mechanism allows fast and easy adjustment of the inner ring without special tools
• Locking mechanism positioned behind the outer ring, protected from router damage and excess mudding during drywall finishing
• Adjustment screws located outside the inner ring, preserving the full 15 cubic inch interior capacity for devices and wiring
• Measured rule printed on the inner ring for accurate pre-fabrication setting in pre-drywall installations
• Hot-rolled pre-galvanized steel construction resists corrosion in standard interior environments
• Rounded corner type for safer handling and consistent fitment against finished wall materials

Compatibility

Designed as an OEM-style replacement and standard new-construction fitting for 4-inch square electrical device boxes requiring a two-gang raised plaster ring.

Installation Notes

Installation is performed by a licensed electrician in accordance with NEC requirements for box fill and device mounting. De-energize the circuit at the breaker panel before handling any wiring at the box. Secure the ring to the box using the provided mounting points before applying drywall compound, and verify the inner ring depth is set to match the finished wall surface using the integrated measurement rule. Do not overtighten adjustment screws, as the pre-galvanized steel surface can deform if excessive force is applied.

Technical Specifications

• Box Size: 4 inches
• Opening Type: 2 device (two-gang)
• Raised Height: 1-1/4 inches
• Corner Type: Rounded
• Capacity: 15 cubic inches
• Material: Hot rolled pre-galvanized AISI C-1008 steel, ASTM G90-U, 0.062 inches thick
• Finish: Silver (pre-galvanized)
• Approvals: UL 514A, CSA, FS W-J-800
• Country of Origin: US
• Standard Package Quantity: 25 per carton

Standard Information

• Brand: STEEL CITY
• Manufacturer Part Number: 52-C-21