General Order 95
Section III
Requirements for All Lines
32.4 Circuits of Different Classification on the Same Crossarm
A. Supply Circuits
(1) 750 – 7,500 Volts and More than 20,000 Volts:
Supply circuits of 750 - 7,500 volts shall not be carried on the same crossarm
with circuits of more than 20,000 volts unless the higher voltage circuit
is not energized when men are working at this level. Where this construction
is used, circuits of different classification shall be carried on opposite
ends of the crossarm with a horizontal separation of not less than pin spacing
required for the highest voltage concerned, but not less than 36 inches
between the nearest conductors of different classification.
(2) 0 - 750 Volts and More than 7,500 Volts: Supply circuits
of 0 - 750 volts shall not be carried on the same crossarm with circuits of
more than 7,500 volts, except that, on transformer structures, bus conductors
of 0 - 750 volts and bus conductors of 7,500 - 22,500 volts may be supported
on opposite ends of the same bus–supporting timbers provided the horizontal
separation between conductors of different classifications supported on the
same arm is not less than 36 inches, the bus conductors of 7,500 - 22,500
volts are not extended longitudinally as line conductors, service drops are
not supported on arms which support conductors of 7,500 - 22,500 volts, and
conductors on related buck arms are not less than 4 feet vertically from such
bus timbers.
Note: Revised March 29, 1966 by Decision
No. 70489 and August 9, 1966 by Decision No. 71094.
(3) 0 - 750 Volts and 750 - 7,500 Volts: Supply circuits of 0 - 750 volts
and 750 - 7,500 volts which are owned and operated by the same utility may
be carried on opposite ends of the same crossarm with the nearest conductors
of the two classifications separated a horizontal distance of not less than
36 inches. For requirements applicable to buck arm construction, climbing
space, and service drops on combination arms, see Rule
54.4–C2b
and 54.8–E
respectively.
(4) More than 750 Volts, Different Ownerships: Supply circuits of more than 750 volts and of different ownership may be carried on opposite ends of the same crossarm with the nearest conductors of different ownerships separated a horizontal distance of not less than 36 inches, provided proper ownership designation is maintained.
(5)
0 - 750 Volts, Different Ownerships: Supply circuits of 0 - 750 volts
and of different ownership may be carried on opposite ends of the same crossarm
with the nearest conductors of different ownerships separated a horizontal
distance of not less than 30 inches.
(6) Common Neutral Conductor:
See Rule 59.3–E
for the location of the common neutral conductor in common neutral systems.
B. Supply Circuits
of 0 - 750 Volts and Communication Circuits
Supply circuits of 0 - 300 volts
and Class C communication circuits of different ownership may be supported
on the same crossarm, provided the two classifications of circuits are installed
on opposite ends of the arm and the nearest conductors of the two classifications
are separated a horizontal distance of not less than 36 inches. Where the
two classes of circuits are of the same ownership, the horizontal distance
may be reduced to not less than 30 inches and the supply circuit voltage
may be 0 - 750 volts. Services direct from such a crossarm are not permitted
to cross conductors of the other classification supported on the same crossarm.
C. Supply Circuits
and Private Communication Circuits (see Rules
20.6–A
and 89
)
(1) 7,500 - 22,500 Volts, Same Ownership: Supply circuits of 7,500 - 22,500
volts and private communication circuits owned (or leased) and operated and
maintained by the same organization may be supported on the same crossarms
as provided in Rule 89.2–A1
.
Note: Revised
March 29, 1966 by Decision No. 70489; August 9, 1966 by Decision No.71094;
and January 19, 1994 by Resolution SU–25.
(2) 750 - 7,500 Volts, Same Ownership: Supply circuits of 750 - 7,500 volts
and private communication circuits owned (or leased) and operated and maintained
by the same organization may be supported on the same crossarms as provided
in Rule 89.2–A2
.
(3) 0 - 750 Volts: Supply circuits of 0 - 750 volts and private communication circuits may be supported on the same crossarms as provided in Rule 89.2–A3 , or Rule 89.2–A4 .