Shock And Vibration Requirements - Cisco Nexus 7718 Hardware Installation Manual

Preparing the Site
To predict and prevent strong EMI, you might need to consult experts in radio frequency interference
Note
(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.
If the wires exceed the recommended distances, or if wires pass between buildings, give special consideration
to the effect of a lightning strike in your vicinity. The electromagnetic pulse caused by lightning or other
high-energy phenomena can easily couple enough energy into unshielded conductors to destroy electronic
switches. You may want to consult experts in electrical surge suppression and shielding if you had similar
problems in the past.

Shock and Vibration Requirements

The switch is being shock- and vibration-tested for operating ranges, handling, and earthquake standards to
Network Equipment Building Standards (NEBS) Zone 4 per GR-63-Core.
Grounding Requirements
The switch is sensitive to variations in voltage supplied by the power sources. Overvoltage, undervoltage,
and transients (or spikes) can erase data from the memory or cause components to fail. To protect against
these types of problems, ensure that there is an earth-ground connection for the switch. You can connect the
grounding pad on the switch either directly to the earth-ground connection or to a fully bonded and grounded
rack.
You must provide the grounding cable to make this connection but you can connect the grounding wire to the
switch using a grounding lug that ships with the switch. Size the grounding wire to meet local and national
installation requirements. Depending on the power supply and system, a 12 AWG to 6 AWG copper conductor
is required for U.S. installations (for those installations, we recommend that you use commercially available
6 AWG wire). The length of the grounding wire depends on the proximity of the switch to proper grounding
facilities.
You automatically ground the AC power supplies when you connect them to a power source, but you
Note
cannot ground a 3-kW DC power supply. You must connect the chassis to the facility earth ground.
Planning for Power Requirements
To plan for the power requirements of a switch, you must determine each of the following:
• Power requirements of the switch
• Minimum number of power supplies required to power the switch and its components
• Power mode to use and the number of additional power supplies required for that mode
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Cisco Nexus 7718 Switch Site Preparation and Hardware Installation Guide
Shock and Vibration Requirements
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