Cisco 4948 - Catalyst Switch Installation Manual page 36

System Grounding
Proper grounding practices ensure that the buildings and the installed equipment within them have
low-impedance connections and low-voltage differentials between chassis. When you include
NEBS-compliant system grounds, you reduce or prevent shock hazards, greatly reduce the chances of
equipment damage due to transients, and substantially reduce the potential for data corruption.
Without proper and complete system grounding, you run the risk of increased component damage due to
ESD. Additionally, you have a greatly increased chance of data corruption, system lockup and frequent
system reboot situations by not using a system (NEBS compliant) ground.
Installations that rely solely on system grounding using only an AC third-prong ground run a
Caution
substantially greater risk of equipment problems and data corruption than those installations that use
both the AC third-prong ground and a properly installed system (NEBS compliant) ground.
Table 2-1
Table 2-1
Environment
Commercial building is
subjected to direct lightning
strikes.
For example, some places in the
United States, such as Florida,
are subject to more lightning
strikes than other areas.
Commercial building is located
in an area where lightning storms
frequently occur but is not
subject to direct lightning
strikes.
Commercial building contains a
mix of information technology
equipment and industrial
equipment, such as welding.
Existing commercial building is
not subject to natural
environmental noise or
man-made industrial noise. This
building contains a standard
office environment. This
installation has a history of
malfunction due to
electromagnetic noise.
Catalyst 4948E and Catalyst 4948E-F Switch Installation Guide
2-8
lists some general grounding practice guidelines.
Grounding Practice Guidelines
Electromagnetic
Noise Severity Level
High
High
Medium to High
Medium
Chapter 2 Preparing for Installation
Grounding Recommendations
All lightning protection devices must be
installed in strict accordance with
manufacturer recommendations. Conductors
carrying lightning current should be spaced
away from power and data lines in
accordance with applicable
recommendations and codes. Best grounding
practices must be closely followed.
Grounding best practices must be closely
followed.
Grounding best practices must be closely
followed.
Grounding best practices must be closely
followed. Determine source and cause of
noise if possible, and mitigate as closely as
possible at the noise source or reduce
coupling from the noise source to the victim
equipment.
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