Grounding antennas on rooftops
1. Bond each antenna mount/mast to the CGB with No. 2 AWG BTCW exothermically
welded to the mast and connected to the ground bar with an approved two- hole
ground lug.
2. Install coax ground kits as close to the antennas as possible, just before the antenna
jumpers, and then bonded to the CGB.
Note If the site configuration is such that the coax runs horizontally along the rooftop
and then vertically down the side of the building to the close mount antennas, Do Not
Install antenna masts or coax ground connections at the antenna.
Instead, install a CGB at the roof edge where the coax transitions from horizontal to
vertical. Install coax ground kits as close to the edge as possible where the coax is still
horizontal and bond the ground leads to the CGB. Connect the CGB to the MGB in
the usual manner.
3. Connect each antenna CGB to the MGB at the equipment location.
4. If the MGB is located on the rooftop, use one run of No. 2 AWG BTCW to bond the
CGB to the MGB. Run this along the coax cable tray on the rooftop and secure to the
cable tray to prevent wind damage.
Note Due to the fact that the cable tray runs along the roof and the MGB is typically
installed at a slightly higher elevation, it may be necessary for ground leads to run
slightly upward to bond to the MGB. If this cannot be avoided, ensure that all ground
wire bends are smooth and have as large a radius as possible.
5. If the equipment MGB is located inside the building, a separate external ground bar is
located where the coax enters the building. All No. 2 AWG BTCW sector grounds
bond to this ground bar. In addition, install a coax ground kit on each coax cable and
bond it to the ground bar. This external ground bar connects to the interior MGB
using a single 4/0 AWG stranded, insulated wire installed along the coax path.
Cable Tray Grounding
All metallic cable tray on a rooftop, mounted on the side of a building, or running inside a
building, must be properly grounded.
To ground a cable tray
1. A metallic cable tray must be grounded to the sector CGB at one end and grounded to
the MGB at the other end using No. 2 AWG BTCW.
2. Connect the ground wire to the cable tray with two-hole multiple crimp type (with UL
tool and circumferential die compression) connections attached with bolts or self-
tapping screws.
3. Each section of the cable tray must be electrically connected by either a metal plate or
ground jumpers made of No. 2 AWG BTCW and two-hole lugs.
4. If the equipment MGB is located inside the building, the cable tray ground connects
to the external ground bar where the coax enters the building.
114 TDC-0971-011 CCU 100 and Repeater 100 Installation Guide
Proprietary and Confidential
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