Cisco Systems 274, 474 manual Using Power Protection Devices, Surge Protectors

Appendix B Maintaining the Wide Area Virtualization Engine

Using Power Protection Devices

–Teletype machines

–Adding machines

–Laser printers

–Facsimile machines

–Any other motorized equipment

Besides these appliances, the greatest threats to a system’s supply of power are surges or blackouts 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.

Using Power Protection Devices

A number of devices are available that protect against power problems such as power surges, transients, and power failures. The following subsections describe some of these devices:

•Surge Protectors, page B-7

•Line Conditioners, page B-8

•Uninterruptible Power Supplies, page B-8

Surge Protectors

Surge protectors are available in a variety of types and usually provide a level of protection commensurate with the cost of the device. Surge protectors prevent voltage spikes, such as those caused during an electrical storm, from entering a system through the electrical outlet. Surge protectors, however, do not offer protection against brownouts, which occur when the voltage drops more than 20 percent below the normal AC line voltage level.

	Cisco Wide Area Virtualization Engine 274 and 474 Hardware Installation Guide
OL-17739-01		B-7