Cleanness; Emi; Laser Safety - NEC QX-S5500G Series Installation Manual

Installation Guide
QX-S5500G Series Ethernet Switches

2.3.2 Cleanness

Dust buildup on the chassis may result in electrostatic adsorption, which causes poor
contact of metal components and contact points, especially when indoor relative humidity is
low. In the worst case, electrostatic adsorption can cause communication failure.
Dust
 Note:
Dust diameter ≥ 5 μm
The equipment room must also meet strict limits on salts, acids, and sulfides to eliminate
corrosion and premature aging of components, as shown in Table 2-2
SO
2
H S
2
NH
3
Cl
2

2.3.3 EMI

All electromagnetic interference (EMI) sources, from outside or inside of the switch and
application system, adversely affect the switch in a conduction pattern of capacitance
coupling, inductance coupling, electromagnetic wave radiation, or common impedance
(including the grounding system) coupling. To prevent EMI, take the following actions:
Please take the effective measures to reduce the intervention the power supply

system exerts on the switch.
Keep the switch far away from high-power radio launchers, radars, and equipment

with high frequency or high current.
If AC power is used, use a single-phase three-wire power receptacle with protection

earth (PE) to filter interference from the power grid.
Keep the switch far away from radio transmitting stations, radar stations, and

high-frequency devices.
Use electromagnetic shielding, for example, shielded interface cables, when

necessary.
Route interface cables only indoors to prevent signal ports from getting damaged by

overvoltage or overcurrent caused by lightning strikes.

2.3.4 Laser safety

The QX-S5500G Series switches are Class 1 laser devices.
Table 2-1 Dust concentration limit in the equipment room
Substance
≤ 3 x 10
Table 2-2 Harmful gas limits in the equipment room
Gas
0.2
0.006
0.05
0.01
Concentration limit (particles/m³)
(no visible dust on the tabletop over three days)
4
Maximum concentration (mg/m3)
2-3
2. Preparing for installation