Line-interactive UPS for Offices and Small Servers

A line-interactive UPS is the workhorse of the office. It passes the mains power to the equipment, corrects small rises and falls in the voltage without touching the battery, and switches to the battery when the supply fails.

It costs less than an online UPS and suits most offices, shops and small server rooms.

Key takeaways

• It corrects voltage changes with a transformer, so the battery is saved for real cuts.
• It switches to the battery within a few milliseconds when the supply fails.
• It suits computers, network equipment, point-of-sale systems and small servers.
• Very sensitive equipment may need an online UPS instead.

How it works

In normal use the mains supply goes through the UPS to the equipment, and a transformer in the UPS raises or lowers the voltage a little when it is too low or too high. If the supply is lost or goes out of range, the UPS switches to the battery and its inverter makes the power for the equipment. When the supply returns, it switches back and recharges the battery.

Where it fits

• Office computers and printers that are not the heavy laser type.
• Network switches, routers and Wi-Fi equipment.
• Point-of-sale systems and card machines.
• Small servers and storage boxes.

Choosing one

Add up the watts of the equipment to be protected and choose a UPS whose watt rating is comfortably higher, then choose the backup time you need: a few minutes to save and shut down, or longer if the equipment must stay on until power returns. Look for a sine wave output, because some equipment does not like the stepped waveform of cheaper units.

When to choose online instead

If the equipment is very sensitive, or the supply is very poor, an online UPS gives cleaner power at a higher cost. Our guide to online (double-conversion) UPS explains the difference. For batteries and backup time, see UPS battery configuration.

When to call us

Tell us what you want to protect and we will recommend a UPS of the right size and type. Use the quote page, see our commercial UPS solutions, or look at the UPS systems we supply.