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Guide Topics
NEC Table 310.16
Complete Conductor Ampacities Reference (2023 Edition)
Standard
NFPA 70
Article
310.16
Temperature Range
60°C - 90°C
Critical Code Requirements
This table is based on not more than three current-carrying conductors in raceway, cable, or earth (directly buried), based on an ambient temperature of 30°C (86°F). Adjustments required for different conditions.
Complete Ampacity Table - Copper & Aluminum
| AWG/kcmil | Copper | Aluminum/Copper-Clad | ||||
|---|---|---|---|---|---|---|
| 60°C | 75°C | 90°C | 60°C | 75°C | 90°C | |
| 14 | 15 | 20 | 25 | — | — | — |
| 12 | 20 | 25 | 30 | 15 | 20 | 25 |
| 10 | 30 | 35 | 40 | 25 | 30 | 35 |
| 8 | 40 | 50 | 55 | 35 | 40 | 45 |
| 6 | 55 | 65 | 75 | 40 | 50 | 55 |
| 4 | 70 | 85 | 95 | 55 | 65 | 75 |
| 3 | 85 | 100 | 115 | 65 | 75 | 85 |
| 2 | 95 | 115 | 130 | 75 | 90 | 100 |
| 1 | 110 | 130 | 145 | 85 | 100 | 115 |
| 1/0 | 125 | 150 | 170 | 100 | 120 | 135 |
| 2/0 | 145 | 175 | 195 | 115 | 135 | 150 |
| 3/0 | 165 | 200 | 225 | 130 | 155 | 175 |
| 4/0 | 195 | 230 | 260 | 150 | 180 | 205 |
| 250 kcmil | 215 | 255 | 290 | 170 | 205 | 230 |
| 300 kcmil | 240 | 285 | 320 | 190 | 230 | 260 |
| 350 kcmil | 260 | 310 | 350 | 210 | 250 | 280 |
| 400 kcmil | 280 | 335 | 380 | 225 | 270 | 305 |
| 500 kcmil | 320 | 380 | 430 | 260 | 310 | 350 |
| 600 kcmil | 350 | 420 | 475 | 285 | 340 | 385 |
| 750 kcmil | 385 | 460 | 520 | 315 | 375 | 425 |
| 1000 kcmil | 445 | 535 | 615 | 370 | 445 | 500 |
Note: 75°C column (highlighted) is most commonly used for residential and commercial applications. Terminations typically rated at 75°C per NEC 110.14(C).
Temperature Correction Factors
| Ambient Temperature | 60°C | 75°C | 90°C |
|---|---|---|---|
| 10°C or less | 1.29 | 1.2 | 1.15 |
| 11-15°C | 1.22 | 1.15 | 1.12 |
| 16-20°C | 1.15 | 1.11 | 1.08 |
| 21-25°C | 1.08 | 1.05 | 1.04 |
| 26-30°C(Standard) | 1 | 1 | 1 |
| 31-35°C | 0.91 | 0.94 | 0.96 |
| 36-40°C | 0.82 | 0.88 | 0.91 |
| 41-45°C | 0.71 | 0.82 | 0.87 |
| 46-50°C | 0.58 | 0.75 | 0.82 |
| 51-55°C | 0.41 | 0.67 | 0.76 |
| 56-60°C | — | 0.58 | 0.71 |
Example: #12 AWG copper at 75°C = 25A. In 40°C ambient: 25A × 0.88 = 22A adjusted ampacity
Conductor Bundle Adjustment Factors
Current-Carrying Conductors
| Number of Conductors | Adjustment Factor |
|---|---|
| 1-3 | 1.00 |
| 4-6 | 0.8 |
| 7-9 | 0.7 |
| 10-20 | 0.5 |
| 21-30 | 0.45 |
| 31-40 | 0.4 |
| 41+ | 0.35 |
Calculation Example
Scenario: Six #10 AWG THHN copper conductors in conduit
- 1. Base ampacity (75°C): 35A
- 2. Bundle factor (6 conductors): 0.80
- 3. Adjusted ampacity: 35A × 0.80 = 28A
Neutral conductors carrying only unbalanced load are not counted
Common Circuit Applications
| Circuit Type | Copper Wire | Aluminum Wire | Temp Rating | Common Uses |
|---|---|---|---|---|
| 15A General Purpose | 14 AWG | 12 AWG | 60°C | Lighting, receptacles |
| 20A Kitchen/Bath | 12 AWG | 10 AWG | 60°C | Small appliances, bathroom |
| 30A Dryer | 10 AWG | 8 AWG | 75°C | Electric dryer, window AC |
| 40A Range | 8 AWG | 6 AWG | 75°C | Electric range, cooktop |
| 50A Hot Tub | 6 AWG | 4 AWG | 75°C | Spa, EV charger |
| 100A Subpanel | 3 AWG | 1 AWG | 75°C | Garage, workshop |
| 200A Service | 3/0 AWG | 4/0 AWG | 75°C | Main service entrance |
Related Calculators & Tools
Important Notes & Exceptions
Terminal Temperature Limitations
- Conductors with 90°C insulation can use 90°C ampacity only if terminations are rated 90°C
- Most residential/commercial equipment has 75°C terminations
- Circuits 100A or less: assume 60°C unless marked otherwise
- Circuits over 100A: may use 75°C if equipment is rated
When NOT to Use This Table
- Conductors in free air (use Table 310.17)
- Bare or covered conductors (use Table 310.21)
- Underground installations with specific conditions
- Motor circuits (see Article 430 for special requirements)
Download NEC Table 310.16 PDF
Get a printable reference for field use