Original Version
Rule 59.3-B
59.3-B. Size
In common neutral systems the common neutral line conductor shall have a cross-sectional area approximately 50 percent or more of the area of the largest related primary phase conductor, as set forth in Table No. 14 and in no case shall have less conductivity or mechanical strength than No. 6 AWG medium-hard-drawn copper wire.
Table 14 Relative Sizes of Common Neutral System Line Conductors |
|
Size of Primary phase conductor (cir mils or AWG) |
Minimum size of neutral conductor (AWG) |
500,000 |
4/0 |
350,000 |
3/0 |
250,000 |
2/0 |
4/0 |
1/0 |
3/0 |
1 |
2/0 |
2 |
1/0 |
3 |
1 |
3 |
2 |
6 |
4 |
6 |
5 |
6 |
This Table is based on the requirement that the common neutral line conductor
shall have a minimum area of approximately 50 per cent of the area of the
largest related primary phase conductor and that the phase and neutral conductors
are of the same material. Where these are not of the same material,
the copper conductance equivalents of the table will be considered as meeting
the requirements.
Strikeout and Underline Version
Rule 59.3-B
59.3-B. Size
In common neutral systems the common neutral line conductor shall have a cross-sectional area approximately 50 percent or more of the area of the largest related primary phase conductor, as set forth in Table No. 14 and in no case shall have less conductivity or mechanical strength than No. 6 AWG medium-hard-drawn copper wire.
Table 14 Relative Sizes of Common Neutral System Line Conductors |
|
Size of Primary phase conductor (cir mils or AWG) |
Minimum size of neutral conductor (AWG) |
| 715,000 |
350,000 |
500,000 |
4/0 |
350,000 |
3/0 |
250,000 |
2/0 |
4/0 |
1/0 |
3/0 |
1 |
2/0 |
2 |
1/0 |
3 |
1 |
3 |
2 |
6 |
4 |
6 |
5 |
6 |
This Table is based on the requirement that the common
neutral line conductor shall have a minimum area of approximately 50 per
cent of the area of the largest related primary phase conductor and that
the phase and neutral conductors are of the same material. Where these
are not of the same material, the copper conductance equivalents of the table
will be considered as meeting the requirements.
Final Version
Rule 59.3-B
59.3-B. Size
In common neutral systems the common neutral line conductor shall have a cross-sectional area approximately 50 percent or more of the area of the largest related primary phase conductor, as set forth in Table No. 14 and in no case shall have less conductivity or mechanical strength than No. 6 AWG medium-hard-drawn copper wire.
Table 14 Relative Sizes of Common Neutral System Line Conductors |
|
Size of Primary phase conductor (cir mils or AWG) |
Minimum size of neutral conductor (AWG) |
| 715,000 |
350,000 |
500,000 |
4/0 |
350,000 |
3/0 |
250,000 |
2/0 |
4/0 |
1/0 |
3/0 |
1 |
2/0 |
2 |
1/0 |
3 |
1 |
3 |
2 |
6 |
4 |
6 |
5 |
6 |
This Table is based on the requirement that the common neutral line conductor
shall have a minimum area of approximately 50 per cent of the area of the
largest related primary phase conductor and that the phase and neutral conductors
are of the same material. Where these are not of the same material,
the copper conductance equivalents of the table will be considered as meeting
the requirements.