Steel City 4" Octagonal Box, 1/2" Depth

The box gives you 15.8 cubic inches of volume, which is the number you work your NEC fill calculation from. At 2.25 cubic inches per 14 AWG conductor that works out to seven 14 AWG conductors, or six 12 AWG at 2.5 cubic inches each, before you deduct for devices, clamps, and grounds. One ground group counts as a single conductor, and a fixture stud or hickey counts as one more.

Five knockout configurations are offered: 1/2 inch only (54151 1/2), 3/4 inch only (54151 3/4), combination 1/2 and 3/4 inch (54151 1/2 & 3/4), plus two clamp-nail versions, 54151 1/2 CN and 54151 1/2 3/4CN. Pick the combination knockouts if you want the flexibility to land either 1/2 or 3/4 inch trade size connectors on the same box, and the CN versions if you want the integral nails for fastening to framing.

No. The 54151 octagon box is not weatherproof, so it belongs in dry interior locations only. For a wet or damp exterior fixture you need a listed weatherproof box with gasketed cover, not this drawn steel box.

The Steel City 54151 is a drawn steel 4-inch diameter octagonal ceiling box with a 15.8 cubic inch capacity, intended for wall or ceiling mounting of a single outlet. For a fan hang, specify a box built and marked for fan support instead, such as the RACO 295-1 round fan-rated ceiling pan in 4-inch steel from THE INSIDER series, or the Pass & Seymour Reiker drop ceiling fan and fixture support box. Those two are the fan-and-fixture support products in the group; the 54151 is the general-purpose octagon.

Yes. At 101.6mm (4 inches) across, the 54151 takes the standard 4 inch octagonal round covers, blanks, and fixture canopies with the usual 2-3/4 inch on-center mounting holes. That is why it is the default box for standardizing light outlets across a building.

The 54151 is drawn steel, so it bonds through the raceway or cable armor and suits EMT or MC work in commercial ceilings. If you are in residential NM cable or want no metal in the assembly, a nonmetallic option like the Allied Moulded 9304 fiberglass reinforced ceiling fixture support box or the PC244OW FlexBox is the direction to go. Steel also takes a fixture stud and the hard knocks of a plaster or drywall ceiling better.

Yes. The 54151 ships as the box with its knockouts, and nothing else. Any cable connectors or conduit fittings for the knockouts you open, plus the cover or fixture canopy, and knockout seals for the ones you do not use, are separate line items.

The Steel City 54151 is a fixed 4-inch octagonal drawn steel box mounted to wall or ceiling framing, so its position is set when it is fastened. For an adjustable position, the Allied Moulded SB-CB Sliderbox and the Allied Moulded PC244OW FlexBox are the repositionable ceiling fixture support boxes in the group. Choose the 54151 when the outlet location is fixed on the drawing.

They are both 4-inch steel ceiling boxes, so they cover the same opening diameter: the 54151 is 4 inches in diameter with a 1/2 inch depth designation and 15.8 cubic inches of capacity, and the RACO 295-1 is a round fan-rated ceiling pan in 4-inch steel. The differences are shape and intent - the 54151 is octagonal for general fixture and junction use, while the 295-1 is a round pan rated for fan support. Confirm which the inspector is looking for before swapping.

The Steel City 54151 octagonal box is not a weatherproof box, so keep it to dry interior ceiling and wall outlets. Where a nonmetallic body is preferred for moisture exposure, the Allied Moulded 9304 fiberglass reinforced ceiling fixture support box is the fiberglass option in the group; verify the location rating for the specific enclosure against the job spec before ordering.

A 4-inch octagonal box like the Steel City 54151, which is a single-outlet drawn steel ceiling box, is not the part for a drop-mounted fan. The Pass & Seymour Reiker drop ceiling fan and fixture support box is the drop-type fan and fixture support unit among the comparable ceiling boxes.

Both. The 54151 is set up for wall or ceiling mounting, so the same box covers an overhead light outlet and a wall-mounted sconce or junction point. The CN versions carry the clamp nails for fastening directly to a stud or joist face.

Fifty boxes per carton, which is the usual buy for an electrician rough-in or an MRO shelf stocking one standard light outlet box across a property.