4. Bond the CGB to a single ground rod located immediately adjacent to the support
structure using No. 2 AWG BTCW.
Note In all cases, ensure that the grounding design complies with the utility pole
owner’s requirements.
Repeaters on Rooftops
Repeaters located at rooftop sites must have antenna mounts, coax, and coax cable tray (if
required) grounded in the same manner as a full network device.
To ground repeaters on rooftops
1. Locate the MGB at the repeater equipment location.
2. Bond , in order of preference, to one of the following:
• existing building lightning or ground protection system
• building steel
• one 4/0 AWG down conductor to ground rod or cold water main.
Multiple Story Site Ground System
If the site is in a high rise building or in a metropolitan area with very limited access to
any earth, then a water pipe electrode with a single chemical ground rod for augmentation
is specified. This should yield as low a noise ground system as possible even if it is not
exactly a five ohm ground.
Down Conductors Installation - Building / Shelter Penetrations
Use Schedule 40 or 80 polyvinyl chloride (PVC) conduit to carry the required down
conductors, penetrating the outer wall and foundation of each building at ground level.
Using steel conduit is unacceptable since it significantly increases the conductor's
inductance.
Down Conductors Installation - Limits of Bend Radius
Connect the inside halo ground and the BGR with conductors that follow a path as
straight and vertical as possible with no bend having a radius of less than eight inches.
Deviations can cause increased inductive reactance leading to excessively high voltage
and/or flash over during a lightning strike.
Down Conductors Installation Connection Methods
Use an approved exothermic welding system to connect all down conductors to the BGR.
TDC-0971-011 CCU 100 and Repeater 100 Installation Guide 117
Proprietary and Confidential
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