Huawei USG6000E Series Hardware Manual page 604

HUAWEI USG6000E Series
Hardware Guide
Item
Incoming
power cables
DC distribution
grounding
Equipotential
bonding
Common
grounding
requirements
Issue 08 (2022-04-20)
Requirement
AC and DC power cables should not be led into or out of the
communications station through overhead lines.
After low-voltage power cables are led into the equipment
room, in the AC voltage regulator and AC power distribution
box (PDB), install a lightning arrester for power cables and
connect the lightning arrester to the nearest grounding post.
If the equipment room is located in an urban area, the AC
power system of the equipment room should have a lightning
protection unit with a nominal discharge current of no less
than 20 kA. If the equipment room is located in a suburban
area that is classified as a medium or high level lightning zone,
install a lightning protection unit with a nominal discharge
current of greater than 60 kA. If the equipment room is
located in a mountainous area that is classified as a high-level
lightning zone or in an isolated building in an urban area,
install a lightning protection unit with a nominal discharge
current of greater than 100 kA.
The ground cable of the lightning arrester used for the power
supply must be shorter than one meter.
The DC working ground of the communications station (the
positive pole of the -48 V DC power supply or the negative
pole of the 24 V DC power supply) should be led in from the
nearest indoor main earthing conductor.
The device that supplies power to the communications station
should provide the DC working ground that connects from the
collective ground cable of the building (or from the protection
ground bar in the equipment room) to the power supply.
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 the 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.
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