How to Size Solar Wiring in India
Undersized cables cause energy loss, overheating, and fire risk. The key formula: Cross-section (sq mm) = (2 × Length × Current × ρ) / (V × allowed V-drop%) where ρ = 0.0172 for copper.
Standard Sizes Used in India
- DC strings (small residential): 4 sq mm PV cable
- DC strings (large / long runs): 6 sq mm PV cable
- AC output (single phase, 5 kW): 6–10 sq mm copper
- AC output (three phase, 10 kW+): 6–16 sq mm copper
Safety Note: Always use UV-resistant, double-insulated, solar-rated (PV) cables for DC runs. Standard house wire is NOT suitable outdoors for solar DC.