600 kcmil THHN Copper Ampacity
600 kcmil copper THHN: 475A base at 90°C, 420A usable after 110.14(C) termination limit.
Base475A
Usable420A
NEC Table310.16
Full derating calculation
Applications
600 kcmil copper handles high-capacity commercial and industrial feeders.
Voltage drop by distance
| Distance (ft) | 240V Drop | % Drop | Verdict |
|---|---|---|---|
| 50 ft | 0.9V | 0.4% | OK |
| 75 ft | 1.4V | 0.6% | OK |
| 100 ft | 1.8V | 0.8% | OK |
| 150 ft | 2.7V | 1.1% | OK |
| 200 ft | 3.6V | 1.5% | OK |
| 250 ft | 4.5V | 1.9% | OK |
| 300 ft | 5.4V | 2.2% | OK |
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NEC 2023 references verified April 2026