General Order 64-A
Detailed Construction Requirements For Supply Lines
(Class H, L and T Circuits)
54.6 Protective Covering (See Rule 22.1.)
A. Vertical Runs.
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.)
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.
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
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.)
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.
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.