Steel City 52151 BX 4-Inch Square Steel Outlet Box, 21 in³, 1/2-In KO

The Steel City 52151 BX has a 21 cubic inch volume, which is what you size your conductor fill against under the NEC box fill table. At 2.25 cubic inches per 14 AWG conductor that works out to nine 14 AWG conductors, or eight 12 AWG at 2.25 and 2.5 cubic inches respectively (ten 12 AWG would need 25 cubic inches). Remember every device counts as two conductors of the largest wire in the box, all clamps together count as one, and all grounds together count as one.

Both are on the box already. The 52151 BX is supplied with a mounting bracket for fastening to a stud and with integral cable clamps, so you are not adding a separate bracket or buying clamp assemblies to secure NM cable. What you still need to order is the cover or device ring, which is not part of the box.

No. This is a plain steel 4 inch square box with open knockouts and a stud bracket, built for dry interior wall and ceiling work. For an exterior or wet location use a weatherproof box instead, such as the Mulberry Royal Mountie die-cast aluminum weatherproof 1-gang box, or the Thomas & Betts 2IH3-1 Red-Dot 2-gang conduit outlet box with three 1/2 inch hubs where you're coming in with conduit.

No. The 52151 BX is a standard steel 4-inch square outlet box listed under UL E2969 for ordinary locations. For classified areas the Appleton GRJ Series and GRJS Series are explosionproof malleable iron conduit outlet boxes; Appleton also offers the GRT75 as a malleable iron round conduit outlet box. Those are threaded conduit bodies, not a drop-in replacement for a square device box.

The Cantex EZ Series is a PVC multi-gang residential outlet box, so it is the nonmetallic route for the same kind of device rough-in. The difference that matters is material and bonding: the 52151 BX is steel, which carries the equipment ground through the raceway or clamped cable, while a PVC box requires the ground to be carried in the wiring. The 52151 BX also holds 21 cubic inches with 11 knockouts.

Yes. At 4 by 4 inches with a 1-1/2 inch depth, the 52151 BX takes the standard 4 inch square covers and raised device rings (single gang, two gang, or flat blank) that every 4S box uses. Pick the ring depth to match your finished wall thickness so the device sits flush.

Steel is what you want where the wiring method is EMT or where the job spec or local amendment calls for metal raceway and a bonded metallic box, and the 52151 BX gives you that with its bracket and clamps for a stud mount. For plain residential NM work in non-metallic systems, a PVC box like the Cantex EZ Series multi-gang residential box is the usual choice, and it needs no bonding of the box itself. Gang requirements often decide it too: this one is a single 4 inch square.

For a dedicated range or dryer receptacle, the Pass and Seymour P242RRD is a thermoplastic range and dryer box built for that application. The Steel City 52151 BX is a general-purpose 4-inch square steel box measuring 4 by 4 by 1-1/2 inches with 21 cubic inches of volume, sized for standard device and junction use rather than for a range or dryer assembly.

The 52151 BX is a 4-inch square steel box with 11 knockouts sized at 1/2 inch, a mounting bracket and built-in clamps, so it nails to framing and accepts clamped cable. The Appleton GRT75 is a malleable iron round conduit outlet box, a threaded fitting used in the run of rigid conduit rather than a bracketed device box. They serve different points in a wiring system and are not interchangeable.

The Steel City 52151 BX is a single 4-inch square steel box at 4 by 4 by 1-1/2 inches and 21 cubic inches, typically used with a cover or plaster ring for one or two devices. When the opening calls for a ganged nonmetallic box, the Cantex EZ Series is a PVC multi-gang residential outlet box; in a weatherproof metal assembly, the Thomas and Betts 2IH3-1 Red-Dot is a 2-gang conduit outlet box with three 1/2-inch hubs.

The Steel City 52151 BX sells each, so the quantity you enter is the number of individual boxes. If you're rough-in buying by the hundred, order the count you need rather than assuming a carton multiple. For comparison, some conduit boxes we carry are packed by the case, like the Thomas & Betts 2IH3-1 Red-Dot box in packs of 100.

Country of origin is the United States. For a government, school, or transit job carrying a domestic-content requirement, that's the origin on record for this box.