600 kcmil Wire Ampacity & Specifications
NEC ampacity, resistance and typical uses for 600 kcmil copper and aluminum wire.
Calculations are built on the 2023 National Electrical Code (NEC) and cross-checked against the published code tables. How we verify. Last reviewed June 2026.
Copper 75°C
420A
Copper 90°C
475A
Aluminum 75°C
340A
Typical breaker
400A
600 kcmil Wire Specifications
| Ampacity — Copper (60 / 75 / 90°C) | 350 / 420 / 475 A |
| Ampacity — Aluminum (60 / 75 / 90°C) | 285 / 340 / 385 A |
| Cross-section | 600,000 circular mils |
| DC resistance — Copper | 0.0214 Ω / 1000 ft |
| DC resistance — Aluminum | 0.0353 Ω / 1000 ft |
| Typical voltage drop (240V) | 0.4% at 50 ft · 0.7% at 100 ft (at 400A) |
Common Uses for 600 kcmil Wire
- 420A copper feeders
- Service entrances (often paralleled)
Ampacities are from NEC Table 310.16. 14, 12 and 10 AWG are limited to 15A, 20A and 30A overcurrent protection (240.4(D)). Terminations rated 60°C or 75°C usually cap the usable ampacity below the 90°C value.
Sizing a circuit?
Use the calculator to size wire for your current, distance and voltage.