User's Manual

Electromagnetism Requirements for the Equipment Room
All interference sources, inside or outside the equipment room, can cause equipment problems
with capacitive coupling, inductive coupling, electromagnetic wave radiation, and common
impedance (including grounding system) coupling. Prevent the interference using these
approaches:
l Take effective measures against electrical interference from the power supply system.
l Do not use the working ground of the equipment as the same ground for surge protection.
Separate them as far as possible.
l Keep the equipment far away from high-power radio transmitters, radar units, and high-
frequency and high-current equipment.
l Use electromagnetic shielding if necessary.
Requirements for Lightning Proof Grounding
Table 5-13 lists the requirements for lightning proof grounding.
Table 5-13 Requirements for lightning proof grounding
Item Requirements
Capital
construction
l Use reinforced concrete to construct the equipment room.
l Install a lightning proof device like a lightning rod outside the room.
l The lightning proof ground shares the same grounding body with the
protective ground of the room.
Power cables
leading in the
equipment room
need to be
equipped with a
surge protector
l After the low-voltage power cables are led into the room, install the
surge protector for the power cables in the AC voltage stabilizer and
the AC power distribution panel (box). Correctly ground the surge
protector nearby.
l For an equipment room in urban area, install a power supply surge
protector with the nominal discharge current of no less than 20 kA.
For an equipment room that is built in a suburb and subject to lightning
strikes, install a power supply surge protector with the nominal
discharge current of more than 60 kA. For an equipment room that is
built in a mountain area and subject to frequent lightning strikes, or in
a separate high-rise building in a city, install a power supply surge
protector with the nominal discharge current of more than 100 kA.
l The ground cable of the surge protector should be no longer than 1 m
(3.28 ft).
Grounding for
DC power
distribution
l 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.
l The power equipment must have a DC working ground cable, which
can connect the power equipment to the collective ground cable of the
telecommunication site (or the protective ground bar of the equipment
room).
AP3x10xN&5x10xN&5x30xN&6x10xN&7x10xN
Hardware Installation and Maintenance Guide 5 Appendix
Issue 12 (2015-08-05) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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