Sizing up UPS

Uninterruptible power supplies (UPS) vary in capacity, providing backup power for individual PCs, enterprise data centers and everything in between.

A voltage-ampere (VA) rating determines the load a given UPS can carry. Officials determine how much backup power the organization needs by adding the power requirements for each device to be supported. Multiplying a device's amp rating by the line voltage provides an estimate of VA.

A UPS with 300VA may be suitable for protecting a single PC. In March, Tripp Lite debuted a line of low-profile UPS systems