Reference · NEC 2023
Table 310.16 — conductor ampacities
Base conditions: ≤3 current-carrying conductors, 30°C (86°F) ambient. Values are facts from NFPA 70. Verify against your locally adopted edition.
Copper (selected sizes)
| Size | 60°C | 75°C | 90°C |
|---|---|---|---|
| #14 | 15 | 20 | 25 |
| #12 | 20 | 25 | 30 |
| #10 | 30 | 35 | 40 |
| #8 | 40 | 50 | 55 |
| #6 | 55 | 65 | 75 |
| #4 | 70 | 85 | 95 |
| #3 | 85 | 100 | 115 |
| #2 | 95 | 115 | 130 |
| #1 | 110 | 130 | 145 |
| #1/0 | 125 | 150 | 170 |
| #2/0 | 145 | 175 | 195 |
| #3/0 | 165 | 200 | 225 |
| #4/0 | 195 | 230 | 260 |
| 250 kcmil | 215 | 255 | 290 |
| 300 kcmil | 240 | 285 | 320 |
| 350 kcmil | 260 | 310 | 350 |
| 400 kcmil | 280 | 335 | 380 |
| 500 kcmil | 320 | 380 | 430 |
| 600 kcmil | 350 | 420 | 475 |
| 750 kcmil | 400 | 475 | 535 |
| 1000 kcmil | 455 | 545 | 615 |
Aluminum (selected sizes)
| Size | 60°C | 75°C | 90°C |
|---|---|---|---|
| #12 | 15 | 20 | 25 |
| #10 | 25 | 30 | 35 |
| #8 | 35 | 40 | 45 |
| #6 | 40 | 50 | 55 |
| #4 | 55 | 65 | 75 |
| #2 | 75 | 90 | 100 |
| #1 | 85 | 100 | 115 |
| #1/0 | 100 | 120 | 135 |
| #2/0 | 115 | 135 | 150 |
| #3/0 | 130 | 155 | 175 |
| #4/0 | 150 | 180 | 205 |
| 250 kcmil | 170 | 205 | 230 |
| 350 kcmil | 210 | 250 | 280 |
| 500 kcmil | 260 | 310 | 350 |
| 750 kcmil | 320 | 385 | 435 |
| 1000 kcmil | 375 | 445 | 500 |
Temperature correction — 310.15(B)(1)
- 78–86F (26–30C): 60°C ×1 · 75°C ×1 · 90°C ×1
- 87–95F (31–35C): 60°C ×0.91 · 75°C ×0.94 · 90°C ×0.96
- 96–104F (36–40C): 60°C ×0.82 · 75°C ×0.88 · 90°C ×0.91
- 105–113F (41–45C): 60°C ×0.71 · 75°C ×0.82 · 90°C ×0.87
- 114–122F (46–50C): 60°C ×0.58 · 75°C ×0.75 · 90°C ×0.82
Bundling — 310.15(C)(1) + 240.4(D)
- 1–3 CCC → ×1.00
- 4–6 CCC → ×0.80
- 7–9 CCC → ×0.70
- 10–20 CCC → ×0.50
- 21–30 CCC → ×0.45
- 31–40 CCC → ×0.40
- 41+ CCC → ×0.35
240.4(D): Cu 14→15A · 12→20A · 10→30A; Al 12→15A · 10→25A.