Side-by-Side Comparison
Electrical & Wiring
AWG Wire Sizes vs. Circuit Breaker Sizes & Amperage
Comparing 2 standards across 18 specifications. 18 key differences identified.
Comparing:
AWG Wire Sizes
Circuit Breaker Sizes & Amperage
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.
Residential and commercial circuit breakers are standardized under National Electrical Code (NEC Article 240) and UL 489 into standard continuous trip ratings (15A, 20A, 30A, 40A, 50A, 60A, 100A, 200A), single-pole (120V) vs double-pole (240V) formats, and mandatory AFCI/GFCI protection types.
Specification Comparison Table
18 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards
|
ASTM B258 / National Electrical Code (NEC) Chapter 9 Table 8 | NFPA 70 (NEC) / UL 489 / NEMA AB 1 (Circuit Breakers) |
|
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 | — |
|
15-Amp Single Pole (120V)
|
— | Wire Gauge: 14 AWG Copper | Standard residential lighting and general bedroom/living outlets |
|
20-Amp Single Pole (120V)
|
— | Wire Gauge: 12 AWG Copper | Kitchen countertop, bathroom receptacles, laundry, garage, workshop |
|
30-Amp Double Pole (240V)
|
— | Wire Gauge: 10 AWG Copper | Electric clothes dryers, 30-gallon water heaters, small RV hookups |
|
40-Amp Double Pole (240V)
|
— | Wire Gauge: 8 AWG Copper | Electric cooking ranges, cooktops, heat pump auxiliary heat |
|
50-Amp Double Pole (240V)
|
— | Wire Gauge: 6 AWG Copper | Level 2 EV charging (NEMA 14-50), commercial cooking ovens |
|
60-Amp Double Pole (240V)
|
— | Wire Gauge: 4 AWG Copper (or 6 AWG THHN) | Central air conditioning compressors, sub-panel feeds |
|
100A–200A Main Service
|
— | 2/0 AWG Copper / 4/0 AWG Aluminum | Main residential service disconnect panel |
|
80% Continuous Load Rule
|
— | NEC 210.20: Continuous loads (operating 3+ hours) must not exceed 80% of breaker rating (e.g. 16A max on 20A breaker) |