400A wire size at 48V over 50 ft (copper)
No standard single conductor satisfies both ampacity and a 3% voltage-drop target for 400A at 48V over 50 ft. Raise the system voltage, shorten the run, or use parallel conductors.
Why this size
At 48V, voltage drop usually decides the conductor before ampacity does — the lower the voltage, the more the drop matters over distance. CircuitProof sizes to whichever constraint is stricter, then cites the code basis used. For this 50 ft run at 400A, the limiting factor is none.
Aluminum runs about two AWG sizes larger than copper for the same load, and continuous loads add a 125% factor. Always confirm terminations and breaker ratings against the installed conductor.
Related
Planning aid only — not a P.Eng/PE stamp. Verify with a licensed electrician and applicable codes (NEC, ABYC, CSA) before installation.