Huawei NE05E Hardware Manual page 406

HUAWEI NE05E,NE08E
Hardware Guide
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In the past surge protection grounding of the building was separate from the
grounding for telecom system and power supply system, and a large distance was
required between the grounding objects. However, the distance requirement is not
satisfied due to small space of the building. In fact, they cannot be separated in
most cases, so joint grounding system is recommended for the lightening
protection grounding of the building. The joint grounding system shall connect the
telecom BGND, PGND, surge protection grounding of the building, and grounding
of the power frequency AC power supply system. A high earth resistance of the
joint grounding system is required. The earth resistance required by
telecommunication is far lower than 10 ohms, and the grounding requirements for
different telecom devices vary, so the resistance of the joint grounding system
should be determined according to the minimum resistance required for the
grounding device.
It is recommended to use steel bars in the walls and pillars of the building as
ground cables for lightening protection. These wires should be electrically
connected so as to equalize the electric potential in the building.
Condensation Prevention
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Issue 05 (2023-03-31)
are protruding from the building. The cross-sectional area of the grounding
wire of the surge protection device should not be smaller than 120 mm
while the space between the wires not larger than 30 m.
The earth resistance of the earthing/grounding system is recommended to be
less than 10 ohms, and the equipment grounding should be in accordance
with national and local electrical codes as well.
Outdoor cables and metal pipes should be grounded before entering the
building, and the outdoor cables should be equipped with lightening
protection devices at the inlet of the building.
It is suggested to use roof plates, beams and pillars made of reinforced
concrete and the reinforcement bar as the ground cables of lightening
arresters.
Before installing the equipment, ensure that no condensation is on the
equipment. Otherwise, the equipment may fail to be powered on.
If the indoor and outdoor temperature difference is 15°C or more, wait eight
hours after moving devices to the equipment and then install them.
Generally, when the outdoor humidity is greater than 80% and the indoor and
outdoor temperature difference is greater than 5°C, condensation forms. In
highly humid weather, before installing a device or board, you are advised to
remove the package inside an equipment room and check whether
condensation forms as follows: Touch the surface of the device or board with
dry fingers or ESD gloves to check whether water marks exist. If they do,
condensation forms, and the device or board must be kept in the equipment
room for 8 hours before being powered on.
NO TE
If the temperature difference is undetermined, wait one night before installing the
equipment.If the temperature difference is undetermined, wait one night before
installing the equipment.
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