Huawei USG6000 Series Hardware Manual page 411

HUAWEI USG6000 Series
Hardware Guide
Item
Equipotential
bonding
Common
grounding
requirements
Grounding
resistance
Signal cable
layout
Collective
ground cable
Grounding lead-
in cable
Issue 08 (2017-06-30)
Requirement
The communications devices and auxiliary facilities in the equipment
room must be properly grounded. These devices and facilities include
mobile base transceiver stations (BTSs), transmission devices,
switching devices, power supply, and distribution frames. All the
devices in the communications station should be grounded to the same
ground busbar. All devices in an equipment room should be grounded
to the same protection ground bar in the equipment room.
A ground grid must be shared by the working grounds and protection
grounds of all devices in the equipment room.
The cable tray, iron suspension racks, racks, chassis, metal ventilation
pipes, and metal doors and windows must be grounded.
The neutral of the AC power cables must not be connected to the
protection ground of any communications device in the equipment
room.
Do not install switches or fuses on the ground cables.
Ground cables should be as short and straight as possible and should
not be coiled.
Less than 1 Ohm
The upper end of the ground body must be no less than 0.7 m from the
ground. In cold regions, the ground body should be buried under the
frozen soil layer.
Measure the grounding resistance periodically to ensure that the
grounding works properly.
No overhead signal cable should exist in the communications station.
Signal cables should be led into the station from underground.
The communications cables led into or out of the communication
station should be protected with metal sheaths or laid out in metal
pipes.
The ground cable of a lightning arrester should be as short as possible.
The unused wire pairs in the cables should be grounded in the
equipment room.
The main earthing conductor can be a cable grounding ring or busbar.
Do not use aluminum materials as ground cables. Avoid
electrochemical corrosion when different types of metals are
interconnected.
Generally, a copper busbar with a cross-sectional area of no less than
2
120 mm or galvanized steel with the same resistance is used as the
main earthing conductor. The main earthing conductor must be
insulated from the reinforcing steel bar in the building.
The grounding lead-in cable must be no longer than 30 m. The
grounding lead-in cable should use galvanized steel with a cross-
sectional area of 40 mm x 4 mm or 50 mm x 5 mm.
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