Images for Q & A Page > 5S 277/480/ 4wire /3cts

Images for the question asked by Dan. First, in answering his question based on a more thorough mathematical and direct approach, I would need to begin with a few assumptions: ONE: that these figures and calculations are going to be based on unity power factor and a balanced 3-Phase load. TWO: that “a” and “b” [lowercase] are referencing the secondary labels and that B A C [uppercase] are also referring to secondary labels. [I say this because generally lowercase a,b,c refers to secondary labels and uppercase A,B,C refer to primary labels.] THREE: that the ‘b’ and ‘a’ CTs were swapped or mis-wired and that the voltages to the meter potential coils have remained in their correct positions.