Devoted to hardware, software, IT issues, and information technology management

Most, if not all, of the equipment supporting a company's IT infrastructure is electromechanical and that means that hardware (hard drives, NICs, network switches, power supplies, servers, even utilities) will eventually fail or experience an outage of some kind.

In the case of power, the Uninterruptible Power Supply (UPS) provides some level of protection against an outage.  Not every company can afford a backup generator, but most data centers do rely on free-standing, rack-mount or room UPS as an alternate power source.  American Power Conversion Corp. (APC) and Tripp Lite are some of the more well-known manufacturers.

Regarding UPS capabilities:

• Usually the purpose behind the UPS is to provide enough runtime to gracefully shutdown the equipment attached.  Some models support the addition of battery packs to extend runtime.
• The battery packs can eventually fail and will need to be replaced.  Most UPS automatically self-test the battery packs and have a visual indicator to identify when the packs need to be replaced or the UPS requires maintenance.
• The UPS conditions the incoming utility power to protect against surges, spikes, lightning and other power disturbances.
• Certain models will support the addition of network management or environmental monitoring cards.
• Some companies package software with the UPS to automatically shutdown the attached equipment if utility power is lost.

If a UPS purchase is on the horizon, consider the following:

• UPS capacity is measured in Volt-ampere (VA), but the "true power" it is capable of providing is measured in Watts (W) and is usually much lower than VA.  Assess the equipment you plan to support with the UPS and confirm the total Watts don't exceed the UPS capacity.
• Don't load the UPS 100% as this will severly limit the available runtime.  Leaving excess capacity will extend runtime and accommodate new equipment.
• Verify that you have the appropriate input power (120V, 208V or 230V) and connections (5-20P, L6-20P, L6-30P or even hardwire) to support the UPS.
• Ensure the UPS has the appropriate output power (120V, 208V or 230V) and connections to support equipment to be attached.  If you exhaust the connections before the UPS capacity has been reached, it may also be necessary to purchase a Power Distribution Unit (PDU).

Don't rely completely on a single UPS.  If you have equipment with redundant power supplies, connect them to different power sources (ex. one connected to utility power with a PDU to condition that power and one to the UPS or distribute the connections amongst multiple UPS).