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Dust and Particulate Requirements
(low pressure), the efficiency of forced and convection cooling is reduced and can result in electrical problems
that are related to arcing and corona effects. This condition can also cause sealed components with internal
pressure, such as electrolytic capacitors, to fail or to perform at a reduced efficiency.
Dust and Particulate Requirements
Exhaust fans cool power supplies and system fans cool switches by drawing in air and exhausting air out
through various openings in the chassis. However, fans also ingest dust and other particles, causing contaminant
buildup in the switch and increased internal chassis temperature. A clean operating environment can greatly
reduce the negative effects of dust and other particles, which act as insulators and interfere with the mechanical
components in the switch.
In addition to regular cleaning, follow these precautions to avoid contamination of your switch:
• Do not permit smoking near the switch.
• Do not permit food or drink near the switch.
Minimizing Electromagnetic and Radio Frequency Interference
Electromagnetic interference (EMI) and radio frequency interference (RFI) from the switch can adversely
affect other devices, such as radio and television (TV) receivers, operating near the switch. Radio frequencies
that emanate from the switch can also interfere with cordless and low-power telephones. Conversely, RFI
from high-power telephones can cause spurious characters to appear on the switch monitor.
RFI is defined as any EMI with a frequency above 10 kHz. This type of interference can travel from the switch
to other devices through the power cable and power source or through the air as transmitted radio waves. The
Federal Communications Commission (FCC) publishes specific regulations to limit the amount of EMI and
RFI that can be emitted by computing equipment. Each switch meets these FCC regulations.
To reduce the possibility of EMI and RFI, follow these guidelines:
• Cover all open expansion slots with a blank filler plate.
• Always use shielded cables with metal connector shells for attaching peripherals to the switch.
When wires are run for any significant distance in an electromagnetic field, interference can occur between
the field and the signals on the wires with the following implications:
• Bad wiring can result in radio interference emanating from the plant wiring.
• Strong EMI, especially when it is caused by lightning or radio transmitters, can destroy the signal drivers
Note
To predict and prevent strong EMI, you might need to consult experts in radio frequency interference (RFI).
The wiring is unlikely to emit radio interference if you use twisted-pair cable with a good distribution of
grounding conductors. If you exceed the recommended distances, use a high-quality twisted-pair cable with
one ground conductor for each data signal when applicable.
Cisco Nexus 9348GC-FXP ACI Mode Hardware Installation Guide
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and receivers in the chassis and even create an electrical hazard by conducting power surges through
lines into equipment.
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