Installation Manual
H3C S7500E Series Ethernet Switches
Chapter 2 Installation Preparations
2-4
2.2.2 Cleanness Requirements
Dust is a big harm for the normal operation of the switch. The indoor dust accumulated
on the chassis can cause electrostatic adsorption, resulting in the poor contact of the
connector or metal contact point. This happens more frequently when the relative
indoor humidity is low, which will not only shorten the service life of the switch, but also
cause communication failure.
The required specifications on dust content and particle diameter in an equipment room
are shown in Table 2-2.
Table 2-2
Dust concentration limit in the equipment room
Physical active substance
Concentration limit (particles/m³)
Dust particle
≤
3 x 10
4
(No visible dust on desk over three days)
Note: Dust particle diameter
≥
5µm
Except the requirements on dust, rigorous requirements on ingredient of salts, acids
and sulfides of air in an equipment room are also set. These harmful gases will speed
up the metal corrosion and the aging processes of certain parts. The equipment room
should be protected from the invasion of harmful gases such as SO
2
, H
2
S, NO
2
, NH
3
and Cl
2
, the value limits of which are shown in the following table:
Table 2-3
Limits on harmful gases in the equipment room
Gas
Maximum concentration (mg/m3)
SO
2
0.2
H
2
S 0.06
NH
3
0.05
Cl
2
0.01
2.2.3 Anti-static Requirements
Any possible interference sources, no matter outside or inside the system, affect the
switch in use may in a way of capacitance coupling, inductance coupling, radiation of
electromagnetic wave, common impedance (including the grounding system) coupling
or conducting line (power line, signaling line and transmission line etc.).Therefore, the
following should be considered:
z
Adopt effective measures to protect the power supply system against the power
grid interference.
z
Separate the working ground of the switch from the ground device of the power
supply equipment or lightning-protection ground device as far as possible.