Long 120 V Branch Circuit to an Outbuilding: 14.48% Voltage Drop

A 300 ft, 20 A branch circuit in 12 AWG copper carrying 15 A to a remote outbuilding. The calculation gives a 17.37 V drop (14.48%), leaving 102.6 V at the load, well over the 3% design limit, so the conductors need enlarging or the run shortening.