SU25 GO128 rule 36.3

A. Materia

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.

A. Materia

Neutral conductors shall be of suitable ~~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~~ an ampacity of not less than one–quarter (25%) that 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. provided that the short time ampacity of the neutral conductor is maintained. The short time ampacity of a neutral conductor is either: the current that a non–insulated conductor can carry for the time which the current flows without annealing, melting, or separating; or the current that an insulated conductor can carry for the time that the current flows without damaging the insulation. In no case shall neutral conductors be smaller than the equivalent of No.6 A WG Copper.

No neutral conductor need have a greater ampacity than either the phase conductor which would supply the ground current, or the maximum current which can flow through the neutral conductor to the ground or electrode of the neutral grid system. The neutral conductor shall have a short time ampacity adequate for the fault current which can flow in the neutral conductor for the operating time of the system protective device. If this value cannot be readily determined, the continuous ampacity of the neutral conductor shall not be less than the full load continuous current of the system supply transformers or other source of supply. In no case shall the neutral conductor have less ampacity than #6 AWG copper.

A. Materia

Neutral conductors shall be of suitable corrosion-resistant material.

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 an ampacity of not less than one–quarter (25%) that of the largest related phase conductor, provided that the short time ampacity of the neutral conductor is maintained. The short time ampacity of a neutral conductor is either: the current that a non–insulated conductor can carry for the time which the current flows without annealing, melting, or separating; or the current that an insulated conductor can carry for the time that the current flows without damaging the insulation. In no case shall neutral conductors be smaller than the equivalent of No.6 A WG Copper.

No neutral conductor need have a greater ampacity than either the phase conductor which would supply the ground current, or the maximum current which can flow through the neutral conductor to the ground or electrode of the neutral grid system. The neutral conductor shall have a short time ampacity adequate for the fault current which can flow in the neutral conductor for the operating time of the system protective device. If this value cannot be readily determined, the continuous ampacity of the neutral conductor shall not be less than the full load continuous current of the system supply transformers or other source of supply. In no case shall the neutral conductor have less ampacity than #6 AWG copper.