Item Requirements
General
requirements for
grounding
l Do not connect the neutral line of the AC power cable with the
protective ground of any telecom equipment in the equipment room.
l Do not install a fuse or switch on the ground cable.
l All ground cables should be as short as possible, and arranged in a
straight line.
Grounding
resistance
l The grounding resistance must be lower than 1 ohm.
l 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.
l Measure the grounding resistance periodically to ensure effective
grounding.
Routing of
signal cable
l Do not arrange the signal cables overhead in the equipment room.
All signal cables must be led into the site underground.
l Use the cables with a metal jacket or place them into a metal pipe if
they come out/in the equipment room.
l Ground the idle lines inside the cable in the equipment room.
l Signal cables should be deployed on internal walls. Do not deploy
outdoor aerial cables.
l Keep signal cables away from power cables and surge protection
devices.
Collective
ground cable
l Use a ground ring or ground bar for the collective ground cable.
l Do not use aluminum cables as ground cables. Adopt measures to
prevent electrification corrosion when connecting different metal
parts together.
l Use a copper busbar as the collective ground cable with a cross-
sectional area of no less than 120 mm
2
(0.19 in.
2
), or use the
galvanized flat steel of the same resistance. Insulate the collective
ground cable from the reinforcing steel bars of the building.
Grounding lead-
in
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 mm x 4
mm (1.58 in. x 0.158 in.) or 50 mm x 5 mm (1.97 in. x 0.197 in.).
13.3.2 Requirements for Power Supply
Requirements for AC Power Supply
An AC power supply system consists of power mains, uninterruptible power supplies (UPSs),
and self-supplied electric generators. In addition to meeting the requirements of the server
load, the AC power supply must have a simple connection line, safe operation, flexible
scheduling, and easy maintenance.
S2700&S3700&S5700&S6700 Switch
Hardware Installation and Maintenance Guide
13 Appendix
Issue 13 (2017-11-20) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
149
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