Steel City 52151 X 4-Inch Square Steel Outlet Box, 21 in³, MC Clamp

The 52151 X comes with MC clamps built into the box, so MC or AC cable lands directly in the box without separate cable connectors. It is a 4 x 4 x 1-1/2 inch steel square box with 11 knockouts for conduit or other wiring methods.

At 21 cubic inches, the 52151 X gives you the volume NEC box fill is calculated against. Using the standard NEC fill allowances, that works out to ten 14 AWG conductors (2.00 in3 each), nine 12 AWG (2.25 in3), or eight 10 AWG (2.50 in3) before deductions for devices, clamps, and grounds. Internal cable clamps count as one deduction at the largest conductor size, and each device yoke counts as two, so a single 12 AWG receptacle in this box uses 2.25 for the clamps plus 4.50 for the yoke plus 2.25 per grounding group.

It is a standard 4 x 4 inch square (4S) box, so the usual 4-inch square flat covers, single-gang and two-gang raised plaster rings, and extension rings all fit the same hole pattern. The 1-1/2 inch depth is the deep 4S format, which is what gets you the 21 cubic inch volume. Rings and covers are ordered separately.

The Steel City 52151 X is a 21 cubic inch steel 4-inch square box with an MC clamp, built for dry interior work where MC cable is pulled into the box. For an exposed exterior location, a weatherproof box is the right choice instead: the Mulberry Royal Mountie is a die-cast aluminum 1-gang weatherproof outlet box, and the Thomas & Betts 2IH3-1 Red-Dot is a 2-gang conduit outlet box with three 1/2 inch hubs for threaded conduit entry.

The Steel City 52151 X is a standard steel outlet box listed under UL E2969 with 11 knockouts and an MC cable clamp, which is general-purpose construction. Classified locations call for an explosionproof box: Appleton's GRJ series and GRJS universal conduit outlet boxes are explosionproof malleable iron, and the Appleton GRT75 is a malleable iron round conduit outlet box in the same family of threaded-conduit fittings.

The steel 52151 X suits commercial and MRO work where the wiring method is MC cable or conduit, it bonds through the metal raceway, and the 11 knockouts give you multiple entry points. For residential NM cable rough-in on studs, a nonmetallic box like the Cantex EZ Series PVC multi-gang residential box is the usual choice instead, since it needs no bonding and is multi-gang out of the box. For a dedicated range or dryer outlet, the Pass & Seymour P242RRD thermoplastic range and dryer box is purpose-built.

Yes. The Steel City 52151 X is a 4 inch by 4 inch by 1-1/2 inch steel box with a built-in MC clamp, which suits metal-clad cable runs. Where non-metallic cable is being used in a house, the Cantex EZ Box is a PVC multi-gang residential outlet box and covers that application without a metal clamp.

Both are metal boxes, but they land in different systems. The Steel City 52151 X is a 4-inch square steel box with 11 knockouts and an MC cable clamp, so cable is clamped into a knockout opening. The Thomas & Betts 2IH3-1 Red-Dot is a 2-gang conduit outlet box with three 1/2 inch threaded hubs and is supplied in a pack of 100, so it is used where rigid or IMC conduit threads directly into the body.

Yes, country of origin on the 52151 X 4-square box is the United States.

The 52151 X is sold each, so one box per unit ordered. If you need bulk packaging for a large rough-in, the Thomas & Betts Red-Dot 2IH3-1 is one example we carry in a pack of 100, though that is a weatherproof conduit box rather than a 4-square.

The Steel City 52151 X is square, measuring 4 inches by 4 inches by 1-1/2 inches deep. If the opening calls for a round body, the Appleton GRT75 is a malleable iron round conduit outlet box and is the round-profile option in the comparable range.