US duplex receptacle wall plate: opening numbers — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/wall-plate-duplex-us/  (sheet CC BY 4.0)
Basis: Arrow Hart / Hubbell Wallplate Dimensional Information (J-2); the opening drawing could not be read, so numbers only
Catalog version: 2026-10-20

Sizes: see table below
- The catalog prints three duplex opening numbers: 0.76 in (19.4 mm), 1.31 in (33.3 mm) and 2.65 in (67.4 mm). The text of the page does not say which number belongs to which part of the outline, so Xem publishes no file: guessing the outline would break the true-size rule.
- A retailer describes the opening as 1-1/8 in high by 1-11/32 in wide at the widest point of each half, with flat tops and bottoms. That differs from the catalog, so measure your own plate before designing a cover.
- Plate outlines, gang spacing and screw spacing are the same as on the toggle and Decora plate pages. Duplex plates use one centre screw into the receptacle.
- Plate thickness, edge radii and bevel are not published.

parameter  value
opening numbers as printed  0.76 in (19.4 mm), 1.31 in (33.3 mm), 2.65 in (67.4 mm)
outline, gang spacing  see the toggle plate page
device mounting-strap hole spacing, box ears  3-9/32 in (83.3 mm)

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Arrow Hart / Hubbell Wiring (via Elliott Electric): Wallplate Dimensional Information, catalog pages J-2 and J-3 — web — Publisher's page; dimensions are facts — https://www2.elliottelectric.com/Media/68-EWD-1045-1-Other
- Kyle Switch Plates: Screw hole spacing on electrical wall plate covers — web — Publisher's page; dimensions are facts — https://kyleswitchplates.com/screw-hole-spacing-on-electrical-wall-plate-covers

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=wall-plate-duplex-us