Rigid (RMC), IMC and EMT conduit sizes to 4 in: outside diameter, wall and inside diameter by trade size, inches and mm

sizes

26 in table

Notes

• Rigid metal conduit (RMC, also called GRC, galvanized rigid conduit): OD and ID by trade size from Wheatland Tube's submittal sheet (ANSI C80.1, UL 6; its OD tolerance is ±0.015 in for 1/2 to 1-1/2 in and ±1% for 2 in and up); walls from BIA's conduit page. BIA prints the rigid OD rounded to 0.1 in (0.8, 1.0, 1.3 ...) so its OD is not used; Wheatland's nominal ID agrees with BIA's wall on every row (OD − ID = 2 × wall to 0.0015 in).
• IMC (intermediate metal conduit, ANSI C80.6): Allied Tube's cut sheet gives OD and wall; BIA's catalog page prints a thicker wall for every size (for 1/2 in: Allied 0.070 in, BIA 0.078 in; for 4 in: 0.140 and 0.150), so both are shown and the ID is computed from Allied's wall. Check the maker's sheet for the one you buy. BIA's rounded IMC OD is not used.
• EMT sizes 1/2 to 2 in are on the emt-conduit page (OD 0.706 to 2.197 in); this page adds 2-1/2 to 4 in from BIA's conduit page (ANSI C80.3): the wall is printed there and the ID is computed. Only one source was read for them. BIA's EMT values for 1/2 to 2 in agree with the emt-conduit page.
• Trade size (and the metric designator 16 to 155) identifies the size; per the Steel Tube Institute 'they are for identification purposes only and are not actual dimensions'. Knockout diameters for the same trade sizes are on the knockout page.
• Left out: thread dimensions and lengths of rigid and IMC (the threads are NPT-style conduit threads with their own lengths), bend radii, coupling and fitting dimensions: the set-screw EMT connector and coupling sheets read (EMCO ERI, O-Z/Gedney) print drawing dimensions as A, B, C without saying which each is, so none is tabulated. No files: a conduit stick is a plain tube; the OD and wall are the numbers.

Rigid (RMC), IMC and EMT conduit sizes to 4 in: outside diameter… size chart

Mating features

Drawn at the exact size. Open press, slide, run and socket features by your process's clearance (tolerances by process); leave designed gaps and clamp fits as drawn.

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Plain text: sheet.txt · JSON: /api/geometry?object=rigid-imc-emt-conduit-sizes-to-4-in

Fits with

Free

EMT conduit sizes: 1/2 to 2 in OD and wall (ANSI C80.3)6 sizes★ 24 filesFree

Conduit knockout diameters (NEMA Bulletin 71): 1/2 to 6 in trade sizes, minimum, nominal and maximum, with bushing and locknut diameters + hole gauge plates298.5×78.7×3.0 mm★ 3 filesFree

Schedule 40 pipe and PVC fittings, 1/2 to 2 inch6 sizes★ 6 filesFree

US PVC device boxes (Carlon, Allied Moulded): size, cubic inches, device screw spacing108.7×25.4×2.0 mm★ sheetFree

US metal handy box and 4 in square box: size, depth, cubic inches, cover ears10 sizes★ sheetFree

Strut channel, 1-5/8 in (Unistrut / B-Line): profile, lips, slots and hole patterns41.27 mm★ 10 filesFree

Outlet raceway for 15-series benches: 24 to 72 in, 2 to 4 duplex outlets4 sizes★ 4 files