Original General Order 128

Section III

Requirements For Supply Systems

36.3    Neutral Conductors

A.    Material

Neutral conductors shall be of copper or other corrosion-resistant material if bare, and may be of aluminum or other material if suitably protected from corrosion.

B.    Size

Neutral conductors shall be of the size required to carry the estimated current to which they may be subjected. As a minimum they shall have a cross sectional area of approximately 50 percent or more of the area of the largest related phase conductor, if of the same material. If the neutral conductor is of material having different conductivity from the phase conductors, such 50 percent requirement shall be adjusted upwards or downwards inversely as the ratio of the conductivities of each material. In no case shall neutral conductors be smaller than the equivalent of No.6 A WG Copper.