This is what we have to follow
310.15(B)(4)(c) On a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, harmonic currents are present in the neutral conductor; the neutral shall therefore be considered a current-carrying conductor.
How much exactly is the major portion of the load?
50.1%?
75%?
Yes many times some of these circuits are feeding non-linear loads but they also feed linear loads.
Each person will have to decide what is the major portion of load.
