Solar Cable Sizer

This calculator determines the appropriate wire gauge (AWG) for connecting solar panels to a combiner box or charge controller, minimizing power loss and ensuring safety.

1. Voltage Drop: The primary goal is to limit voltage drop to an acceptable percentage (e.g., 2-3%). Excessive drop means wasted power. 2. Ampacity: The selected wire must be able to safely carry the maximum current (Isc) of the circuit without overheating. 3. Distance Matters: The longer the wire run, the larger the wire gauge needed to combat voltage drop.

Circular Mil Area (CMA) = (ρ * 2 * L * I) / VD_allowed (where ρ is resistivity of copper, L is length, I is current, and VD is allowed voltage drop)