Cable size for 200 A over 10 m, DC

For 200 A over 10 m on a 24 V DC supply, use at least 150 mm² (300 kcmil AWG) copper cable, protected by a 250 A fuse. Voltage drop: 2.5%.

Assumes copper cable clipped to a wall (or flexible battery cable for DC), 30 °C, PVC insulation. Change anything below.

The same current over other distances

Distance	Cable size	Voltage drop
1 m	70 mm² (2/0 AWG)	0.5%
2 m	70 mm² (2/0 AWG)	1.1%
3 m	70 mm² (2/0 AWG)	1.6%
5 m	70 mm² (2/0 AWG)	2.7%
10 m	150 mm² (300 kcmil AWG)	2.5%

150 mm²
300 kcmil AWG: 250 A
Fuse: 2.5%
Voltage drop: 11 m
2-core cable

Current at the end of the cableDistance (one way)m

Voltage

How the cable runs

Use at least150 mm²300 kcmil AWG

Fuse250 A

Voltage drop2.5% · 0.6 V

Current200 A

Cable carries up to480 A

The distance decides this size: 70 mm² would stay cool enough, but over 10 m it loses too much voltage.

Cores

2 cores (+ and −), or two single cables, red and black

Which cable

Tinned flexible battery cable (ISO 6722 / SAE J1127)

Vans and boats: resists vibration and corrosion.

Welding cable (H01N2-D)

Very flexible, for heavy battery and inverter leads.

Several circuits bundled together carry less each: allow for grouping (IEC 60364-5-52 Table B.52.17).

Guidance based on IEC 60364-5-52 for copper cables. Always check against your local rules (BS 7671, NEC, NF C 15-100, RTIEBT…) and the cable maker’s data.

Planning a whole solar system?Describe it and we size every cable, fuse and part, with a wiring diagram.