Huawei AP4030DN
Hardware Installation and Maintenance Guide
5 Appendix
Issue 02 (2015-05-18)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
73
Item
Requirements
devices.
Collective
ground cable
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
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.).
Grounding of the
cabinet
All the devices including the surge protection device in the cabinet
must be connected in an equipotential manner. The ground cables
can be aggregated to the ground bar or surge protector socket first,
and then the ground bar or surge protector socket is connected to the
ground.
The resistance tested using a multimeter between the device ground
terminals and ground bar cannot exceed 0.1 ohm.
The cabinet can be grounded using the protecting earthing (PE) wire
of the electrical network in the building, zinc-coated angle steel, or
main steel bar of the building.
If the cabinet is grounded using the PE wire of the electrical
network, the grounding status can be checked using a multimeter. If
the voltage between the PE wire and neutral wire is lower than 5 V
and the voltage between the PE wire and live wire is about 220 V,
the PE wire is grounded well. If the tested AC voltages are not
within the ranges, the cabinet must be grounded in other ways.
The yellow-green ground cable contains multiple copper wires. The
diameter is no smaller than 6 mm
2
(0.0093 in.
2
) and the length
cannot exceed 3 m (9.84 ft.).
Ground cables cannot be twisted with signal cables.
Antirust and anticorrosion measures must be taken on the ground
terminals.
The fiber reinforcing rib can be directly connected to the ground bar
of the cabinet. Before wrapping the reinforcing rib with insulation
tape, cut a 0.5 m (1.64 ft.) segment from the reinforcing rib. Wrap
the reinforcing rib with at least five layers of insulation tape. Keep
the reinforcing rib at least 5 cm (1.969 in.) from the cabinet surface.
