standards and guidelines for communication sites - Radio And ...

GROUNDING (EARTHING) SYSTEM COMPONENTS AND INSTALLATION REQUIREMENTS CHAPTER 5: INTERNAL GROUNDING (EARTHING)
Depending on the building construction, building size, communication system requirements, and the
telecommunication cable pathways, one or more communication bonding backbone conductors may be
installed. Each communication bonding backbone conductor shall be consistent with the design of the
communication bonding backbone cabling system, and it shall be installed so that it is protected from
physical damage.
Typically when the equipment rooms or areas are located on different floors of a large multi-story
building, a separate communication bonding backbone conductor is routed up each of the opposite sides
of the building. To equalize potential, the communication bonding backbone conductors are bonded
together with a grounding equalizer conductor at the top floor and at a minimum of every third floor in
between using methods described within this chapter (ANSI-J-STD-607-A-2002).
5.3.6.2 SPECIFICATIONS
All communication bonding backbone conductors and grounding (earthing) equalizer conductors shall
be established of 35 mm 2 csa (#2 AWG) or coarser, solid or stranded copper conductor. When the
conductors are jacketed, they shall be listed for the space in which they are intended to be placed and
the jacket shall be green or properly marked with a distinctive green color (ANSI-J-STD-607-A-2002).
In the buildings that do not have effectively bonded structural steel, additional conductor sizing should
be considered. All communication bonding backbone conductors and grounding equalizer conductors
shall be of the same size. The linear length of a 35 mm 2 csa (#2 AWG) communication bonding
backbone conductor or a grounding equalizer conductor should not exceed 10 m (33 ft.). If a greater
conductor length is required, these conductors should be sized at 2 kcmil per linear foot of conductor
length up to a maximum size of 95 mm 2 csa (#3/0 AWG). See Table 5-3 and Table 5-4 on page 5-27 for
conductor sizing requirements (ANSI-J-STD-607-A-2002; MIL-HDBK-419A).
All communication bonding backbone conductors and grounding equalizer conductors should be
installed without splices. When splices are necessary, the number of splices shall be kept to a minimum
and the splices shall be accessible and located in telecommunication spaces
(ANSI-J-STD-607-A-2002). All communication bonding backbone and grounding equalizer conductor
splices shall be established using suitable methods described within the chapter.
NOTE: The interior water piping system of the building and metallic cable shields shall not be used as
communication bonding backbone conductors or grounding equalizer conductors
(ANSI-J-STD-607-A-2002).
Each equipment area's main SSGB shall be bonded to the communication bonding backbone conductor
or to the grounding equalizer conductor with a grounding conductor of the same size as the
communication bonding backbone conductor using suitable methods described within this chapter. The
building's MGB shall be bonded to the service equipment (power) grounding electrode system using a
grounding conductor of the same size as the communication bonding backbone conductor by using
suitable methods described within this chapter (ANSI-J-STD-607-A-2002).
5-26 68P81089E50-B 9/1/05