WireTheSunCommon cable sizes

Cable size for 200 A over 10 m, DC

For 200 A over 10 m on a 48 V DC supply, use at least 70 mm² (2/0 AWG) copper cable, protected by a 250 A fuse. Voltage drop: 2.7%.

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

DistanceCable sizeVoltage drop
1 m70 mm² (2/0 AWG)0.3%
2 m70 mm² (2/0 AWG)0.5%
3 m70 mm² (2/0 AWG)0.8%
5 m70 mm² (2/0 AWG)1.3%
10 m70 mm² (2/0 AWG)2.7%
70 mm²
2/0 AWG
250 A
Fuse
2.7%
Voltage drop
11 m
2-core cable
How the cable runs
Use at least70 mm²2/0 AWG
Fuse250 A
Voltage drop2.7% · 1.29 V
Current200 A
Cable carries up to315 A

Heat decides this size: it carries the breaker current without overheating, and the voltage drop is fine.

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.