Installation ManualH3C S7500 Series Ethernet Switches Chapter 3 Installation Preparations3-4Table 3-2 Limitation on dust content and diameters in the equipment roomMechanical active material Content limit (particles/m³)Dust particle ≤3 x 10 4 (No visible dust on desk over three days)Note: Dust particle diameter ≥ 5μmBesides, the contents of salt, acid, and sulfide in equipment room shall be strictlyrestricted. Harmful gases will accelerate the corrosion and aging of metal parts. Table3-3 lists the content limit of SO 2, H 2S, NH 3, and CI2 in the equipment room.Table 3-3 Content limits on some harmful gases in the equipment roomGas Maximum (mg/m3)SO 2 0.2H 2S 0.006NH 3 0.05Cl2 0.013.2.3 EMI RequirementsAll possible interference sources, external or internal, affect the switch in the way ofcapacitance coupling, inductance coupling, electromagnetic radiation, and commonimpedance (including the grounding system) coupling. To minimize the influence ofinterference sources on the switch, you should take the following into consideration:z Take effective measures to protect the power supply system against the powergrid interference.z Separate the protection ground (PGND) of the switch from the grounding device orlightning protection grounding device of the power supply equipment as far aspossible.z Keep the switch far away from radio stations, radar, and high-frequency devicesworking in high currents. If necessary, adopt electromagnetic shielding.3.2.4 Grounding RequirementsA good grounding system is the basis for a switch to work stably and reliably and theimportant guarantee of lightning protection, anti-interference and ESD. You shouldprovide a good grounding system for the switch.3.2.5 Power Supply RequirementsThe S7500 series adopt N+1 power supply redundancy (N is 1 or 2).
