Original Version
Rule 59.3-D
59.3-D.
Neutral Conductors
The arrangement and continuity of common neutral conductors
shall conform to the following requirements:
Cross ties of the neutral conductor shall be made to
form a continuous interconnected grid network and there shall be two or more
separate and continuous metallic return conductors from the grid network
to the substation constituting the source of supply thereto.
If two return conductors only are used, each shall have a minimum area of
approximately 50 per cent of the area of the primary phase conductor of the
largest overhead feeder serving the area. (See Table No. 14 of Rule
59.3-B for minimum sizes.)
If more than two return conductors are used, the current-carrying capacity
of the return system shall be such that a break in any one path shall leave
two or more return paths which, combined, shall have a minimum area of approximately
50 per cent of the area of the primary phase conductor of the largest overhead
feeder serving the area, thus providing adequate current-carrying capacity
for full load current. (see Table No. 14 of Rule 59.3-B for minimum
sizes.)
Primary neutral conductors or secondary neutral conductors, where continuous,
may be used as a return loop from a common neutral provided they are of sufficient
current-carrying capacity as specified in Rule 59.3-B and provided that they
are grounded throughout in accordance with the requirements for common neutral
line conductors as specified in Rule 59.4-B. Primary or secondary neutral
line conductors so used shall be carried in their normal primary or secondary
positions respectively.
Strikeout and Underline Version
Rule 59.3-D
59.3-D.
Neutral Conductors
The arrangement and continuity of common neutral conductors
shall conform to the following requirements:
Cross ties of the neutral conductor shall be made to
form a continuous interconnected grid network and there shall be two or more
separate and continuous metallic return conductors from the grid network
to the substation constituting the source of supply thereto.
If two return conductors only are used, each shall have a minimum area conductivity of
approximately 50 per cent of the area conductivity of the primary phase conductor of the
largest overhead feeder serving the area. (See Table No. 14 of Rule
59.3-B for minimum sizes.)
If more than two return conductors are used, the current-carrying capacity
of the return system shall be such that a break in any one path shall leave
two or more return paths which, combined, shall have a minimum area conductivity of approximately
50 per cent of the area conductivity of the primary phase conductor of the largest overhead
feeder serving the area, thus providing adequate current-carrying capacity
for full load current. (see Table No. 14 of Rule 59.3-B for minimum
sizes.)
Primary neutral conductors or secondary neutral conductors, where continuous,
may be used as a return loop from a common neutral provided they are of sufficient
current-carrying capacity as specified in Rule 59.3-B and provided that they
are grounded throughout in accordance with the requirements for common neutral
line conductors as specified in Rule 59.4-B. Primary or secondary neutral
line conductors so used shall be carried in their normal primary or secondary
positions respectively.
Final Version
Rule 59.3-D
59.3-D.
Neutral Conductors
The arrangement and continuity of common neutral conductors
shall conform to the following requirements:
Cross ties of the neutral conductor shall be made to
form a continuous interconnected grid network and there shall be two or more
separate and continuous metallic return conductors from the grid network
to the substation constituting the source of supply thereto.
If two return conductors only are used, each shall have a minimum area of
approximately 50 per cent of the area of the primary phase conductor of the
largest overhead feeder serving the area. (See Table No. 14 of Rule
59.3-B for minimum sizes.)
If more than two return conductors are used, the current-carrying capacity
of the return system shall be such that a break in any one path shall leave
two or more return paths which, combined, shall have a minimum area of approximately
50 per cent of the area of the primary phase conductor of the largest overhead
feeder serving the area, thus providing adequate current-carrying capacity
for full load current. (see Table No. 14 of Rule 59.3-B for minimum
sizes.)
Primary neutral conductors or secondary neutral conductors, where continuous,
may be used as a return loop from a common neutral provided they are of sufficient
current-carrying capacity as specified in Rule 59.3-B and provided that they
are grounded throughout in accordance with the requirements for common neutral
line conductors as specified in Rule 59.4-B. Primary or secondary neutral
line conductors so used shall be carried in their normal primary or secondary
positions respectively.