Six 15-HP continuous-duty motors are connected to a common 480-volt feeder. The nameplate of each motor indicates: Full load amps 18.6, NEMA Code B, and SF 1.10. The conductors supplying each motor are to be copper with THWN insulation, and the feeder conductors supplying all motors are to be copper with THWN insulation. What size conductor should be used to supply each motor and what size conductor should be used for the feeder conductor?