Power protection: surge protectors and UPS units
Updated 9 November 2026 · How-to
A power cut or a surge can destroy equipment and corrupt data. What a UPS does, what to plug into it, and how long it needs to last.
Electricity problems are a quiet cause of IT failures: a lightning strike down the line, a brownout that drops voltage for a second, or a cut that stops a server mid-write. Two inexpensive pieces of equipment prevent most of the damage.
Surge protectors
A surge protector absorbs spikes in voltage before they reach your equipment. Every computer, screen, printer and piece of network equipment should be plugged into one rather than directly into the wall. Cheap power bars often are not surge protectors; look for a joule rating and a protection indicator light. Surge protectors wear out after absorbing surges, so replace any whose indicator light has gone off, and replace them all every few years.
An uninterruptible power supply
A UPS is a battery between the wall and your equipment. When the power fails, it keeps things running for a few minutes, long enough for a server to shut down cleanly instead of crashing, and long enough to ride through the short cuts and flickers that would otherwise reboot everything. It also smooths out brownouts and surges.
What to plug into it
The server, if you have one. The modem, firewall, switch and Wi-Fi access points, so the network stays up during a short cut and your phones and laptops keep working. A desktop computer that holds anything important. Not the printer: laser printers draw a lot of power when warming up and will drain or damage a small UPS.
How big
For a typical small office, a UPS that keeps the network equipment running for 20 to 30 minutes and a server for 10 minutes is enough; the goal is a clean shutdown and riding through brief cuts, not working through an afternoon-long outage. We size it from the actual equipment, and we connect the server to the UPS so it shuts itself down automatically before the battery runs out.
Batteries
UPS batteries last three to five years and then fail, often quietly. A UPS that beeps or shows a battery warning needs a new battery, not to be unplugged. Our monitoring can watch the UPS where the model supports it, and we include battery age in your equipment inventory.
Longer outages
If your business cannot afford to stop for a longer power cut, the answer is a plan to work from elsewhere rather than a bigger battery; see If your office is unavailable.
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