Hi, Frankly, I'm new to this forum. So please do guide me if I posted wrongly. I need some help in sizing the neutral wire. For a 3 phase 4 wire system (3Ph + N), what is the recommended size of the neutral conductor. Should it be the same as the phase conductor or should it be 50% of the phase conductor. Let say a power cable that is sized up to 300sqmm, does the neutral cable also need to be sized to 300sqmm or can it be less? Is there any specific standard, IEC or NEC that mentioned the requirement for neutral conductor size. Appreciate if you guys can mention the IEC or NEC number. Thanks.