NYET You are stuck in DC logic. nununu
Only the n or the u of the sine wave can be occupied by any one phase. Even two phases occupy 66% of the total ampacity. Three phases will occupy 100% of the ampacity. This is why "measuring" neutral is tricky.
Achieving BALANCE of voltages is the crucial element. On a three phase system phase to neutral then phase to phase is vital for a healthy system. I have seen insanely imbalanced 3 phase wye systems down here with 90 volt phases with an orphan measuring 145+ to neutral. This is where a trained electrician earns his money. Above 12 Kv a trained engineer is the best bet. Especially in sub stations where multi transformers of different voltages may be present.
