US PVC device boxes (Carlon, Allied Moulded): size, cubic inches, device screw spacing — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/device-boxes-us/  (sheet CC BY 4.0)
Basis: Maker catalog data (ABB Carlon, Allied Moulded) and Arrow Hart wallplate catalog; only printed numbers
Catalog version: 2026-10-20

Overall (mm): length 108.7, width 25.4, height 2.0
- US nonmetallic (PVC / fibreglass) device boxes, new work and old work: the sizes the makers print, the cubic-inch capacity as marked on the box, and the one position that every device box shares: the device mounting screws, 3-9/32 in apart.
- Sizes are length x width x depth as the maker's catalog data prints them. The data does not say whether an old work box length includes its ears or swing clamps, and two-gang boxes are listed with the long side in different columns, so measure your own box before you cut a wall or print a spacer.
- No drywall cutout is published as a number. Allied says to use its template (1/16 in clearance round the box) or to trace the box; Xem does not guess a cutout from the listed outline.
- The three template files carry what is printed: #6-32 device screw holes (0.138 in major diameter) 3-9/32 in apart at a 46.0 mm gang pitch. They are a design aid for a spacer, extender or smart-switch adapter plate, not a box: box interior, wall thickness and radii are not printed.
- Box fill: the cubic inches are as marked by the maker (NEC 314.16 sets the fill rules; this page does not restate them).

parameter  value
Carlon B114R-UPC old work, 1-gang  14 cu in; 4-1/8 x 2-1/4 x 2-3/4 in (L x W x D)
Carlon B120R old work, 1-gang  20 cu in; 4-1/8 x 2-15/16 x 3-5/8 in
Carlon B225R-UPC old work, 2-gang  25 cu in; 3-15/16 x 3-1/8 x 2-3/4 in
Carlon BH234R old work, 2-gang  34 cu in; 4.3 x 4.36 x 3.59 in
Carlon B355R old work, 3-gang  55 cu in; 5.72 x 2.79 x 3.69 in
Carlon B232BR new work, 2-gang  32 cu in; 3-3/4 x 4 x 3 in
Allied Moulded 9312-E series old work, 2-gang  28.0 cu in; depth 2-3/4, width 4-1/8, height 3-1/4 in
Allied Moulded 9329-EW series old work, 2-gang  32.5 cu in; depth 3-1/4, width 4-1/8, height 3-1/4 in
Allied Moulded 9363-EWK old work, 1-gang  16 cu in; 2-3/8 x 3-1/4 x 2-7/8 in (width x height x depth)
device mounting screws (all gangs)  3-9/32 in (83.3 mm) apart, one pair per device; #6-32 machine screws
gang pitch (device centre to centre)  46.0 mm (1.81 in), from the wall plate catalog
Allied old work cutout rule  template 1TP (1-gang) or 2TP (2-gang) leaves 1/16 in clearance round the box; or trace the box, stopping at the ears
Allied old work ear screws  two #8 sheet metal screws, at least 3/4 in long, one at each end of the box
wall thickness, radii, ear and clamp positions, cutout sizes  not printed as numbers: not modelled

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- ABB (Carlon): B120R 1-gang old work box, catalog data (4-1/8 x 2-15/16 x 3-5/8 in, 20 cu in) — web — Publisher's page; dimensions are facts — https://empower.abb.com/ecatalog/ec/EN_NA/p/B120R
- G.T. Sanders (ABB Carlon data): B114R-UPC old work box (14 cu in, 4-1/8 x 2-1/4 x 2-3/4 in) — web — Publisher's page; dimensions are facts — https://www.gtsanders.com/Product/B114R
- Stoneway Electric (ABB Carlon data): B225R-UPC old work box (25 cu in, 3-15/16 x 3-1/8 x 2-3/4 in) — web — Publisher's page; dimensions are facts — https://www.stoneway.com/product/96915/Shared.ContactForPricing.ContactLink
- Stoneway Electric (ABB Carlon data): BH234R old work box (34 cu in, 4.3 x 4.36 x 3.59 in) — web — Publisher's page; dimensions are facts — https://www.stoneway.com/product/1440/Shared.ContactForPricing.ContactLink
- Crescent Electric (ABB Carlon data): B355R 3-gang old work box (55 cu in, 5.72 x 2.79 x 3.69 in) — web — Publisher's page; dimensions are facts — https://crescentelectric.com/electrical-boxes/outlet-boxes/three-gang-old-work-outlet-box-volume-55-cubic-inches-length-572-inches-width-279-inches-depth-369-inches-color-blue-material-pvc-mounting-means-mounting-ears-and-two-swing-clamps
- Stoneway Electric (ABB Carlon data): B232BR new work 2-gang box (32 cu in, 3-3/4 x 4 x 3 in) — web — Publisher's page; dimensions are facts — https://www.stoneway.com/product/815079/Shared.ContactForPricing.ContactLink
- Allied Moulded (via Elliott Electric): Old work box catalog sheet 9312/9329 series: cubic inches, depths, cutout rule (box plus 1/16 in), screws — web — Publisher's page; dimensions are facts — https://static.elliottelectric.com/Media/9329EWK-ALM
- Stoneway Electric (Allied Moulded data): 9363-EWK old work box (16 cu in, 2-3/8 x 3-1/4 x 2-7/8 in) — web — Publisher's page; dimensions are facts — https://www.stoneway.com/ALLIED-MOULDED-PRODUCTS-9363-EWK-Allied-Moulded-9363-EWK-1-Gang-Switch-Receptacle-Outlet-Box-2-7-8-Inch-Depth-Thermoset-Fiberglass-Reinforced-Polyester-16-Cubic-Inch-Beige-Tan/p2288283
- Arrow Hart / Hubbell Wiring (via Elliott Electric): Wallplate Dimensional Information, catalog pages J-2 and J-3 (gang pitch 46.0 mm, strap spacing 83.3 mm) — web — Publisher's page; dimensions are facts — https://www2.elliottelectric.com/Media/68-EWD-1045-1-Other

No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.
API: https://xemstudio.com/api/geometry?object=device-boxes-us