What is the typical 460 3 phase voltage 1 leg to ground?

230v 230v In a transformer with a primary connected to 480V Delta and a secondary connected in 480V Star connection, the coil voltages to the star point (ground) are 277 volts 480 / 1.73 = 277 volts. Other star connections are 208/120 (208/1.73 = 120V), 600/347 (600/1.73 = 347V). Because the phase angles are not 180 degrees apart they are not additive, they are 120 degrees apart which is why 1.73 factor comes into play.