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Cisco Application Deployment Engine (ADE) 2130 and 2140 Series Appliance Hardware Installation Guide
78-18579-02
Appendix C Maintaining the Cisco ADE 2130 and 2140 Appliance
Maintaining Your Site Environment
Humidity
High-humidity conditions can cause moisture migration and penetration into the appliance. This
moisture can cause corrosion of internal components and degradation of properties, such as electrical
resistance, thermal conductivity, physical strength, and size. Extreme moisture buildup inside the
appliance can result in electrical shorts, which can cause serious damage to the appliance.
Each appliance is rated to operate at 8 to 80 percent relative humidity, with a humidity gradation of
10 percent per hour. Buildings in which climate is controlled by air conditioning in the warmer months
and by heat during the colder months usually maintain an acceptable level of humidity for appliances.
However, if an appliance is located in an unusually humid location, a dehumidifier can be used to
maintain the humidity within an acceptable range.
Altitude
Operating an appliance at high altitude (low pressure) reduces the efficiency of forced, 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.
Electrostatic Discharge
Electrostatic discharge (ESD) results from the buildup of static electricity on the human body and certain
other objects. This static electricity is often produced by simple movements, such as walking across a
carpet. ESD is a discharge of a static electrical charge that occurs when a person whose body contains
such a charge touches a component in the appliance. This static discharge can cause components,
especially chips, to fail. ESD is a problem particularly in dry environments where the relative humidity
is below 50 percent.
To reduce the effects of ESD, you should observe the following guidelines:
• Wear a grounding wrist strap. If a grounding wrist strap is unavailable, touch an unpainted metal
surface on the appliance chassis periodically to neutralize any static charge.
• Keep components in their antistatic packaging until they are installed.
• Avoid wearing clothing made of wool or synthetic materials.
Electromagnetic and Radio Frequency Interference
Warning
Blank faceplates and cover panels serve three important functions: they prevent exposure to
hazardous voltages and currents inside the chassis; they contain electromagnetic interference
(EMI) that might disrupt other equipment; and they direct the flow of cooling air through the chassis.
Do not operate the system unless all cards, faceplates, front covers, and rear covers are in place.
Statement 1029
Electromagnetic interference (EMI) and radio frequency interference (RFI) from an appliance can
adversely affect devices, such as radio and television (TV) receivers operating near the appliance. Radio
frequencies emanating from an appliance can also interfere with cordless and low-power telephones.