Huawei NetEngine80E Installation Manual page 128

HUAWEI NetEngine80E Router
Installation Guide
Item
Grounding of DC
power
distribution
Equipotential
connection
General
requirements for
grounding
Grounding
resistance
Routing of signal
cable
Collective
ground cable
Grounding lead-
in
Issue 02 (2011-09-10)
Requirements
Connect the DC working ground (positive pole of the -48 V DC power
supply or the negative pole of the 24 V DC power supply) with the indoor
collective ground cable nearby. The total ground cable should meet the
maximum load of the equipment.
The power equipment must have the DC working ground cable, which
can connect the power equipment to the collective ground cable of the
telecommunication site (or the protection ground bar of the equipment
room).
Ground the devices and auxiliary devices in the room such as mobile base
station, transmission, switching equipment, power supply equipment, and
cable distribution frame properly. Connect all PGND cables to the
collective protection ground bar. Connect all PGND cables in one
equipment room to one protection ground bar.
Apply joint grounding to the working ground and protection ground of
devices, which means the two share one grounding network.
The cable rack, rack or shell, metal ventilation pipe, metal door or window
of the equipment should be grounded for protection.
Do not connect the neutral line of the AC power cable with the protection
ground of any telecom equipment in the equipment room.
Do not install the fuse or switch on the ground cable.
All ground cables should be as short as possible, and arranged directly.
The grounding resistance must be lower than 1 ohm.
The upper end of the grounding body should be at least 0.7 m (2.30 ft)
over the ground. In cold areas, bury the grounding body below the frozen
ground.
Measure the grounding resistance periodically to ensure effective
grounding.
Do not arrange the signal cables overhead in the equipment room. All
signal cables must be led into the site underground.
Use the cables with metal jacket or place them into the metal pipe if they
come out/in the equipment room.
Ground the idle lines inside the cable in the equipment room.
Use the grounding ring or ground bar for the collective ground cable.
Do not use aluminum cables as ground cables. Adopt measures to prevent
electrification corrosion when connecting different metal parts together.
Use the copper busbar as the collective ground cable with the cross-
sectional area not less than 120 mm
steel of the same resistance. Insulate the collective ground cable from the
reinforcing steel bars of the building.
The grounding lead-in should be a maximum of 30 m (98.42 ft) long. Use
the galvanized flat steel with cross-sectional area of 40 x 4 mm (1.58 in.
x 0.158 in.) or 50 x 5 mm (1.97 in. x 0.197 in.).
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B Environmental Requirements for Device Operation
2 2
(0.19 in. ), or use the galvanized flat
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