General Order 64-A
Section V
Detailed Construction Requirements For Supply Lines
(Class H, L and T Circuits)
54.6 Protective Covering (See Rule 22.1.)
A. Vertical Runs.
(1)
Conductors: Vertical conductors of open wire construction may be
attached to or run on the surface of the pole provided they are suitably
insulated, encased in iron pipe and protected throughout by a suitable
protective covering. Where attached to
steel poles, towers or structures, this protective covering is not required,
provided the wires or cables are suitably insulated and encased in iron pipe
and further provided that both pipe and tower or structure are grounded.
The condulet or other terminal
fitting at the upper end of the vertical runs enclosed in metal conduit or
other conducting material shall be protected by a crossarm or wood block placed
above it at a distance not exceeding 4 inches and said condulet or other
terminal fitting shall not be mounted above the level of its conductors. It is recommended that conductors from such
terminal fittings be carried in a fireproof conduit installed under the arm
from the end of the vertical riser to a point directly beneath the line
conductor to which they are to be connected.
If the terminal fitting or end of
conduit run is on the same side of the pole as, and not more than one foot
directly below the transformer, the wood block may be omitted. The lowest point
of the drip loop from the terminal of the riser or run shall have a minimum
vertical separation of one foot from the nearest conductor level below it.
B. Vertical Risers and Ground Wires. (See Rule 57.7-A and App. G, Figs. 57 and 58.)
(1)
Underground Cables, Conductors, Etc.:
Vertical risers from underground
cables and other conductors shall conform to the following requirements:
The riser shall be protected by a
grounded iron pipe or other metal covering of equal strength from the ground
line to a point not less than 8 feet above the ground.
Any portion of such riser or
cable within a vertical distance of 8 feet from supply conductors (open wires)
or communication conductors on the same pole or within a radial distance of 6
feet from conductors (open wire) supported by another pole or structure shall
be protected by a suitable protective covering. The section of riser between the metal and protective covering
required above shall be covered by the communication of either or both of
them. Where a cable riser is terminated
as illustrated in Figure 58, Appendix G, no provisions of the cable marked “X”
in the figure provided the nearest exposed and energized portion of the
terminal is maintained the minimum distance from the center line of pole
specified for wires in Table 1, Case 7.
Effort should be made to terminate such cables with as little exposed
grounded surface as practicable. The condulet
or other terminal fitting of risers to line conductors shall not be mounted
above the level of said conductors.
Where attached to steel poles,
towers or structures this protective covering is not required provided the
wires or cables are suitably insulated and encased in iron pipe and further
provided that both pipe and tower or structure are grounded.
(2)
Ground Wires: Ground wires may be attached to or run on
the surface of poles, provided they are protected throughout their length by
suitable protective covering. That
portion of the ground conductor below an 8 foot distance from the nearest
supply conductor supported on the pole or structure, or within 6 foot radial
distance of a conductor passing but not attached, requires no protective covering,
provided the line is located in sparsely settled rural areas and the ground
line is of mechanical strength at least equal to No. 4 stranded hard drawn
copper wire.
Contact between the ground wire
and cross arm braces, guy fastenings or other exposed metal parts is permitted
only where it is intended that these elements be grounded and where a positive
electrical contact is made between them and the ground wire. Where this latter provision is exercised, no
circuit within a vertical distance of 3 feet below or 8 feet above such
grounded braces, fastenings or metal parts shall be worked on while any of the
circuits involved are energized. (See
App. G, Fig. 34.)
C.
Grounded Metal Fittings.
All grounded metal boxes and
fittings installed on wood poles or structures shall obtain at least a 6 foot
vertical separation below open wire supply conductors of other circuits. Should it be impracticable to maintain such
vertical clearance, a reduction to 4 feet below supply conductors of 0-750
volts will be permitted provided a suitable protective covering or guard is
used. Cable terminals shall be of a
design that will prevent moisture from entering the cable.
D.
Wood Troughs.
Due care shall be exercised in
the building of the troughs to avoid the possibility of nails protruding
through their inner surface. All
protective covering shall be attached to poles by means of metal straps.
Note This Rule was modified by Supplement 1. To see the changes made by supplement 1 click here. This page contains the wording of the rule prior to Supplement 1.