i have a old 480 3 ph open delta service no neutral and i am adding a 3ph 480/120/240 trans. to run a 240 pump and a dust to dawn lite. i took 3ph and a ground from a 480 disconnect to the trans. in pvc, and a neutral, ground and 3 phases to the 120/240 panel in pvc. bonding to be done in trans.and split in 120/240 panel which is in the same room. do i just connect the 480 side ground to the trans. case, and the net. and ground from the 240v side to xo with a ground jumper from the trans. case to xo.