Chapter 2 Preparing To Install; Altitude; Dust And Particles; Corrosion - Cisco SFS 3504 Hardware Installation Manual

Chapter 2 Preparing to Install

Altitude

Operating a system at high altitude (low pressure) reduces the efficiency of forced and convection
cooling and can result in electrical problems related to arcing and corona effects. This condition can also
cause sealed components with internal pressure, such as electrolytic capacitors, to fail or perform at
reduced efficiency. Ensure that the system is operating in an environment that does not exceed the
specifications in

Dust and Particles

Intake fans within the power supplies cool the power supplies and the system. However, fans also ingest
dust and other particles, causing contaminant buildup in the system 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 system. In addition
to regular cleaning, follow these precautions to avoid contamination of your equipment:
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Corrosion

Corrosion of system connectors is a gradual process that can eventually lead to intermittent failures of
electrical circuits. The oil from the fingers of a person or prolonged exposure to high temperature or
humidity can corrode the gold-plated edge connectors and pin connectors on various components in the
system. To prevent corrosion, avoid touching contacts on boards and cards, and protect the system from
extreme temperatures and moist, salty environments.

Electromagnetic and Radio Frequency Interference

EMI and RFI from a system can adversely affect devices such as radio and TV receivers operating near
the system. Radio frequencies emanating from a system can also interfere with cordless and low-power
telephones. Conversely, RFI from high-power telephones can cause spurious characters to appear on the
system monitor. RFI is defined as any EMI with a frequency above 10 kHz. This type of interference can
travel from the system to other devices through the power cable and power source or through the air like
transmitted radio waves. The FCC publishes specific regulations to limit the amount of EMI and RFI
emitted by computing equipment. Each system meets these FCC regulations. To reduce the possibility
of EMI and RFI, follow these guidelines:
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When wires are run for any significant distance in an electromagnetic field, interference can occur
between the field and the signals on the wires. This fact has two implications for the construction of plant
wiring:
OL-14325-01
Table A-1 on page
Do not permit smoking anywhere near the system.
Do not permit food or drink near the system.
Operate the system only when the chassis cover is installed.
Ensure that all expansion slots are covered either by a card-mounting bracket or by a metal filler
bracket and that all drive bays have either a drive or a metal insert installed.
Ensure that the screws on all peripheral cable connectors are securely fastened to their
corresponding connectors on the back of the chassis.
Always use shielded cables with metal connector shells for attaching peripherals to the system.
A-1.
Cisco SFS 3504 Multifabric Server Switch Hardware Installation Guide
Site Requirements
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