Losses in solar PV wires must be limited, DC losses in strings of solar panels, and AC losses at the output of inverters. A way to limit these losses is to minimize the voltage drop in cables. A drop voltage less than 1% is suitable and in any case it must not exceed 3%. Save electricity : this free online calculator gives the AC and DC Power, Voltage Drop, wire energy losses, resistive heating, for three phase and single phase wiring.