Cisco Systems 4948E-F manual Power Source Interruptions, System Grounding, Shock and Vibration

Chapter 2 Preparing for Installation

Power Source Interruptions

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 devices. If you previously have had similar problems, you might want to consult experts in electrical surge suppression and shielding.

Shock and Vibration

Catalyst 4948E and Catalyst 4948E-F switches have been shock- and vibration-tested for operating ranges, handling, and earthquake standards to NEBS (Zone 4 per GR-63-Core). These tests have been conducted in earthquake environment and criteria, office vibration and criteria, transportation vibration and criteria, and packaged equipment shock.

Power Source Interruptions

Systems are especially sensitive to variations in voltage supplied by the AC power source. Overvoltage, undervoltage, and transients (or spikes) can erase data from memory or even cause components to fail. To protect against these types of problems, power cables should always be properly grounded. Also, place the system on a dedicated power circuit (rather than sharing a circuit with other heavy electrical equipment). In general, do not allow the system to share a circuit with any of the following:

•Copy machines

•Air conditioners

•Vacuum cleaners

•Space heaters

•Power tools

•Teletype machines

•Laser printers

•Facsimile machines

•Any other motorized equipment

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. Both chassis comes with a ground lug and two M4 bolts as part of the accessory kit. The lug attaches to the chassis grounding pad with the two bolts. A 6 AWG copper wire (not provided) must be used to connect the ground lug to the NEBS-compliant building ground.

Catalyst 4948E and Catalyst 4948E-F Switch Installation Guide

OL-21561-02 2-7