System Grounding - Cisco 6503 - Catalyst Firewall Security Sys Installation Manual

Chapter 2 Preparing for Installation
Besides these appliances, the greatest threats to a system power supply are surges or blackouts that are
caused by electrical storms. Whenever possible, turn off the system and any peripherals, and unplug
them from their power sources during thunderstorms. If a blackout occurs—even a temporary
one—while the system is turned on, turn off the system immediately and disconnect it from the electrical
outlet. Leaving the system on may cause problems when the power is restored; all other appliances left
on in the area can create large voltage spikes that can damage the system.

System Grounding

You must install a NEBS-compliant system ground as part of the chassis installation process. Chassis
installations that rely only on the AC third-prong ground are insufficient to properly and adequately
ground the systems.
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.
Caution Installations that rely solely on system grounding using only an AC third-prong ground run a
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 2-3
Table 2-3
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.
OL-5781-08
lists some general grounding practice guidelines.
Grounding Practice Guidelines
Electromagnetic
Noise Severity Level Grounding Recommendations
High
High
Medium to High
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.
Best grounding practices must be closely
followed.
Best grounding practices must be closely
followed.
Catalyst 6500 Series Switches Installation Guide
Site Requirements
2-17