🔌 Cable Size & Voltage Drop
Undersized cable wastes power and melts insulation. Size it right for solar, battery and AC circuits.
Rule of thumb: ≤3% for PV battery circuits (≤2% in the US NEC for critical loads), ≤5% general AC. Use the one-way run length — the return path is calculated automatically.
Recommended cable
How it's computed
DC/1-phase: A = 2·L·I·ρ / (V·drop%) — the ×2 covers the return conductor.
3-phase: A = √3·L·I·ρ / (V·drop%). ρ = 0.0175 Ω·mm²/m (copper), 0.0286 (aluminum) at ~20 °C — for high continuous loads at 70-90 °C, resistance rises ~20-30%; go one size up.
Buying cable with your system?
BESS and inverter suppliers on TUNA ship matched cable kits and connectors.
Source Systems on TUNA →