Side-by-Side Comparison
Electrical & Wiring
Electrical Boxes vs. Electrical Conduit
Comparing 2 standards across 19 specifications. 19 key differences identified.
Comparing:
Electrical Boxes
Electrical Conduit
Standard electrical outlet and junction boxes are specified by trade dimensions and minimum internal cubic inch volume, including 4-inch square boxes (1900/1920 boxes, 21.0–30.3 cu in), 4-inch octagon ceiling boxes (15.5–21.5 cu in), and single-gang device boxes (18.0 cu in).
Electrical conduit sizing is governed by the National Electrical Code Chapter 9 Table 1 40% fill rule for three or more conductors, matching raceway types including Electrical Metallic Tubing (EMT), Schedule 40/80 PVC, and Rigid Metal Conduit (RMC).
Specification Comparison Table
19 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards
|
NEMA OS 1 / NEC Article 314.16 | — |
|
4" Square Box (1-1/2" Deep–1900 Box)
|
4.0 × 4.0 × 1.5 in (102 × 102 × 38 mm) | 21.0 cu in (344 cm³) | — |
|
4" Square Box (2-1/8" Deep–1920 Box)
|
4.0 × 4.0 × 2.125 in (102 × 102 × 54 mm) | 30.3 cu in (496 cm³) | — |
|
4" Octagon / Round Ceiling Box
|
4.0 × 4.0 × 1.5 in (102 × 102 × 38 mm) | 15.5 to 21.5 cu in | — |
|
Handy / Utility Box (Surface 2×4")
|
4.0 × 2.125 × 1.875 in | 13.0 to 14.5 cu in | — |
|
Single-Gang Plastic Device Box
|
Standard 18.0 to 22.5 cu in (supports up to 9 × 14 AWG conductors) | — |
|
Double-Gang Plastic Device Box
|
Standard 32.0 to 35.0 cu in | — |
|
Volume Allowance per 14 AWG Conductor
|
2.00 cu in (32.8 cm³) per wire | — |
|
Volume Allowance per 12 AWG Conductor
|
2.25 cu in (36.9 cm³) per wire | — |
|
Volume Allowance per 10 AWG Conductor
|
2.50 cu in (41.0 cm³) per wire | — |
|
Governing Standard
|
— | NFPA 70 (NEC) Chapter 9, Tables 1, 4, and 5 |
|
1 Conductor Maximum Fill
|
— | 53% of total internal cross-sectional area |
|
2 Conductors Maximum Fill
|
— | 31% of total internal cross-sectional area |
|
3 or More Conductors Max Fill
|
— | 40% of total internal cross-sectional area (Universal Standard) |
|
1/2" EMT Conduit
|
— | ID: 0.622 in (15.8 mm) | Total Area: 0.304 sq in | 40% Usable: 0.122 sq in (9 × 12 AWG THHN max) |
|
3/4" EMT Conduit
|
— | ID: 0.824 in (20.9 mm) | Total Area: 0.533 sq in | 40% Usable: 0.213 sq in (16 × 12 AWG THHN max) |
|
1" EMT Conduit
|
— | ID: 1.049 in (26.6 mm) | Total Area: 0.864 sq in | 40% Usable: 0.346 sq in (26 × 12 AWG THHN max) |
|
2" EMT Conduit (Service Entrance)
|
— | ID: 2.067 in (52.5 mm) | Total Area: 3.356 sq in | 40% Usable: 1.342 sq in (3 × 4/0 Cu THHN) |
|
Schedule 80 PVC vs EMT
|
— | Schedule 80 has heavy thick walls; has ~15–20% smaller internal area than EMT |