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UPS Buying Guide

What is an Uninterruptible Power Supply (UPS)?

An uninterruptible power supply, also called a UPS system, combines a power cord, outlets, power protection, and a built-in battery. The UPS system plugs into your wall outlet, and your devices - such as computers and audio/video components - plug into the UPS system's outlets. Although a UPS system is sometimes called "a battery in a box," it's actually much more. UPS systems can protect and support equipment ranging from a small desktop computer to an entire data center filled with advanced servers and network equipment.

What does a UPS System do?

As long as the electricity stays on, the UPS system passes utility power to the devices connected to its outlets and keeps its internal battery charged. It also protects your devices from power problems it detects, such as power surges and abnormal voltages.

If the power goes out, the UPS system provides connected devices with backup power from its internal battery. This allows your equipment to stay on during a power outage, which is especially useful for devices like computers and DVRs that can lose data when they turn off unexpectedly.

Why do you need power protection?

It would be nice if utility power was always reliable, but it isn't. Between the aging electrical distribution grid, rising power demand, bad weather, and hazards lurking inside your own walls, your equipment is under constant attack from power problems.

Even a brief loss of power or a momentary surge can ruin your valuable equipment and destroy irreplaceable data.

Why is a UPS System a good investment?

For a fraction of the value of the equipment, data, and productivity it protects, a UPS system can prevent damage, downtime, and data loss. It conditions incoming AC power, protects against power problems, provides enough battery backup to outlast most outages, and may even be able to communicate with your computer so it automatically saves open files and shuts down gracefully during an extended outage.

SURGE AND NOISE PROTECTION: Surge protection and line noise filtering components shield your equipment from damage or disruption caused by lightning, surges, and electromagnetic (EMI/RFI) line noise.

VOLTAGE REGULATION: Voltage regulation ensures your equipment will receive voltages that won't cause damage or malfunctions. How the UPS system accomplishes this depends on the type of UPS system, with some types offering more protection than others.

BATTERY BACKUP: The internal battery keeps your connected equipment operating without interruption during a power outage. It also helps the UPS system protect your equipment from other hazards, such as extreme voltage problems.


How much power will your connected equipment require?

Make sure that the UPS can handle the total electrical load of the equipment that you want to connect to it. You can use a Load Calculator to determine your total load, and then choose a UPS with an Output Watt Capacity 20-25% higher than that total.


How much backup runtime do you need?

Runtime is the number of minutes that the UPS will be able to provide power from the battery when utility power fails. Runtime is important because it tells you how long your equipment will continue to run during a power outage before there's no more backup battery power.

Please note that adding more equipment to the UPS will result in a shorter runtime, while adding batteries will increase runtime.


What is the voltage of the equipment you're supporting?

In North America, the voltage used to power servers and networking equipment is typically 120V or 208/240V.

Europe and Asia typically provide 230V power.

Be sure that the UPS input plug matches the receptacles of your input power source.

LCD screen

Do you need an LCD screen?

An LCD screen may allow you to access the advanced features of the UPS system without using a computer. It can also display helpful information, such as input voltage or battery capacity. (Some UPS systems with multiple LEDs can also show this information, though less precisely.) The LCD screen typically has a backlight. If you plan to use the UPS system in a darkened home theater setting, make sure you can dim the backlight to minimize distractions.