Side-by-Side Comparison
Electrical & Wiring
AWG Wire Sizes vs. Electrical Boxes
Comparing 2 standards across 19 specifications. 19 key differences identified.
Comparing:
AWG Wire Sizes
Electrical Boxes
The American Wire Gauge (AWG / ASTM B258) system standardizes solid round electrical conductor diameters based on a logarithmic ratio where 36 AWG equals 0.0050 inches (0.127 mm) and 4/0 (0000) AWG equals 0.4600 inches (11.684 mm) across 39 stepping steps.
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).
Specification Comparison Table
19 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards
|
ASTM B258 / National Electrical Code (NEC) Chapter 9 Table 8 | NEMA OS 1 / NEC Article 314.16 |
|
Geometric Stepping Ratio
|
Ratio between consecutive gauges is 39√(0.4600 / 0.0050) ≈ 1.1229322 | — |
|
Area Doubling Rule of Thumb
|
Decreasing by 3 gauge numbers doubles conductor cross-sectional area and halves resistance | — |
|
Diameter Doubling Rule
|
Decreasing by 6 gauge numbers doubles conductor diameter | — |
|
14 AWG (15A Residential Lighting)
|
Dia: 1.628 mm (0.0641 in) | Area: 2.08 mm² (4,110 cmil) | 8.286 Ω/km | — |
|
12 AWG (20A Small Appliance)
|
Dia: 2.053 mm (0.0808 in) | Area: 3.31 mm² (6,530 cmil) | 5.211 Ω/km | — |
|
10 AWG (30A Water Heater / Dryer)
|
Dia: 2.588 mm (0.1019 in) | Area: 5.26 mm² (10,380 cmil) | 3.277 Ω/km | — |
|
8 AWG (40-50A Electric Range)
|
Dia: 3.264 mm (0.1285 in) | Area: 8.37 mm² (16,510 cmil) | 2.061 Ω/km | — |
|
6 AWG (55-65A Subpanel / Cooktop)
|
Dia: 4.115 mm (0.1620 in) | Area: 13.30 mm² (26,240 cmil) | 1.296 Ω/km | — |
|
4/0 AWG (200A Residential Service)
|
Dia: 11.684 mm (0.4600 in) | Area: 107.2 mm² (211,600 cmil) | 0.1608 Ω/km | — |
|
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 |