General Order 95
Section IX
Joint Poles or Poles Jointly Used
92.4 Grounding
A. General
The following rules cover the grounding or isolating of communication
cable systems, as defined herein. Systems include cables, messengers, and
guys, or a combination of these facilities at the supply or communication
level.
The term “cable” means stranded conductor or a combination
of conductors that includes Fiber Optic Supply Cable, Fiber Optic Communication
Cable, or Non–Dielectric Fiber Optic Cable as defined in
Rule 20.4
.
The term “messenger” is defined in
Rule 22.3
.
The term “guy” is defined in
Rule 21.5
. The definition of “exposed” as applied to a guy in
Rule 21.5–C
shall also apply to cables and messengers.
B. Applicability
The grounding of exposed communication
cable systems includes cables with metallic shields, sheaths, or messenger(s).
The isolating of exposed guys includes both overhead and anchor guys. Exposed
communication cable systems are those that are subject to power contacts,
power induction, or lightning. Cables, messengers, or guys are subject to
power contacts and power induction if they:
(1) Are attached to the same pole as
a supply conductor; or
(2) Cross a supply conductor; or
(3) Are within 8 feet horizontally
and any distance vertically of a supply conductor(s); or
(4) Are attached to the same pole which supports an existing exposed messenger
or guy, even though that pole does not support supply conductors of more than
250 volts.
C. Material and Size
(1) Grounding Conductors: The grounding conductors of the communication
messenger system shall conform to each of the following requirements:
a) The grounding conductor from each ground rod (ground electrode) to the
base of the pole shall not be less than 1 foot below the surface of the ground.
b) The conductor from each ground rod (ground electrode) to the base of
the pole shall not have less ampacity and mechanical strength than the grounding
conductor from the base of the pole to the messenger.
c) The grounding conductor from the ground rod (ground electrode) to the
messenger shall be continuous, unless suitable electrical compression connections
are used.
d) The grounding conductor shall have a minimum ampacity equivalent to
No. 6 AWG copper.
(2) Ground Rods (Ground Electrodes): Ground rods on the communication
messenger system(s) shall conform to each of the following requirements.
a) Ground rods shall be corrosion–resisting metal rods or pipes (or equivalent
in electrical properties)
b) Ground rods shall not be less than 5/8–inch in diameter by 8 feet (total)
in length; this may include two (2) four–foot joined sections.
c) Ground rods shall be driven into the ground so that one end of the
ground rod is at a minimum depth of 8 feet below the surface of the ground.
The top end of the ground rod shall not be less than 1 foot below the surface
of the ground.
d)
Pole–butt plates or wrappings shall not be used either in lieu of the
aforesaid ground rods or pipes, or as electrodes supplementary thereto.
e) The driven ground rod(s), pipe(s), or equivalent shall be located 24
inches or more from the surface of the pole.
D. Location of Grounds on Exposed Cables with Metallic
Shields, Sheaths, or Messengers; and on Exposed Guys
(1)
Exposed Cables and Messengers: The exposed communication cables
and messengers shall be grounded:
At all deadend poles and at intervals not greater than every one–quarter
of a mile (1320 feet).
(2)
Exposed Guys: Communication guys exposed to supply conductors energized
at 22,500 volts or less shall be insulated. Also, see Rules
86.6
, 86.7
and 86.8
.
The grounding of exposed cables, messengers, and guys is in addition to
the ground connections at individual services.
Grounding of exposed messengers near supply electric substations may be
constrained by technical requirements with cooperation between supply and
communication companies.