Appendix C Maintaining the Cisco Wide Area Application Engine

Using Power Protection Devices

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 sections describe some of these devices.

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.

Line Conditioners

Line conditioners go beyond the overvoltage protection of surge protectors. Line conditioners keep a system’s AC power source voltage at a fairly constant level and therefore can handle brownouts. Because of this added protection, line conditioners cost more than surge protectors—up to several hundred dollars. However, these devices cannot protect against a complete loss of power.

Uninterruptible Power Supplies

Uninterruptible power supply (UPS) systems offer the most complete protection against variations in power because they use battery power to keep the system running when AC power is lost. The battery is charged by the AC power while it is available, so once AC power is lost, the battery can provide power to the system for a limited amount of time—from 15 minutes to an hour or so—depending on the UPS system.

 

 

Cisco Wide Area Application Engine 511 and 611 Hardware Installation Guide

 

 

 

 

 

 

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Cisco Systems 611 Using Power Protection Devices, Surge Protectors, Line Conditioners, Uninterruptible Power Supplies