B bsh Senior Member Sep 22, 2009 #1 NEC 240-21(C)(6) (1) discusses primary to secondary voltage ratio. For a 480 volt delta primary to a 120/208 volt wye secondary I have always thought this ratio should be 480 to 208. I have recently been told this should be 480 to 120. Comments?
NEC 240-21(C)(6) (1) discusses primary to secondary voltage ratio. For a 480 volt delta primary to a 120/208 volt wye secondary I have always thought this ratio should be 480 to 208. I have recently been told this should be 480 to 120. Comments?
pete m. Senior Member Location Ohio Sep 22, 2009 #2 The ratio is 480:208 The commentary in the NEC Handbook might provide some guidance. Pete
infinity Moderator Staff member Location New Jersey Occupation Journeyman Electrician Sep 22, 2009 #3 I agree 480/208 = 2.31 factor.
