Line-interactive UPS units protect computers, routers, NAS drives and small servers from power cuts, surges and voltage dips. The range covers tower, compact, desktop and rackmount models from APC, CyberPower, Power Walker and Eaton, with more brands listed below.
How to choose a line-interactive UPS
Load capacity. Add up the wattage of everything you plan to connect and choose a UPS whose watt rating is comfortably higher. VA is not the same as watts, so check both figures. A single PC and monitor needs far less than a rack of servers.
Waveform. Pure sine wave output is the safer choice for computers with active power factor correction power supplies, and for sensitive equipment. Our range includes sine and pure sine models, plus some with stepwise or simulated sine output, which usually suit simpler loads such as routers and basic desktops.
Form factor. Tower and compact units sit under a desk, while desktop models fit on a shelf. Rackmount and rackmount/tower units are made for server cabinets, and the latter can be used either way. Measure your space before ordering.
Outlets and connections. Count the devices and check the socket type. Models in our range offer anywhere from 4 to 10 outlets, using Type E, Type F or IEC C13 sockets, and some larger units also have C19. IEC outlets take standard power cords, which makes them easy to match to your equipment.
Brands we carry
- APC: part of Schneider Electric, known for the Back-UPS and Smart-UPS families used in homes, offices and server rooms.
- CyberPower: offers many line-interactive models with sine wave output, aimed at PCs, networking gear and small servers.
- Power Walker and BlueWalker: BlueWalker is the company behind the PowerWalker brand, which is known for its VI series of line-interactive units.
- Eaton: a power management specialist, known for the Ellipse range for desktops and the 5P and 5S series for rack and tower use.
- Qoltec, Armac and Ever: European brands focused on UPS units for home offices and small businesses.
- Energenie: from Gembird, a maker better known for power strips and surge protection.
Also in our range: Conceptronic, Digitus and FSP Group.
Line-interactive UPS FAQ
What is a line-interactive UPS?
A line-interactive UPS passes mains power to your devices and corrects small voltage swings with an automatic voltage regulator, without switching to battery. It only uses the battery during a full outage or a large drop or surge. This makes it a common choice for home and office equipment.
What is the difference between line-interactive and online UPS?
An online (double-conversion) UPS constantly converts incoming power to battery-backed power and back, so devices never see mains directly. A line-interactive unit is simpler and usually less costly, and it switches to battery only when needed. Online models suit critical servers, while line-interactive models are enough for most desks and small offices.
Do I need a pure sine wave UPS for my PC?
A pure sine wave UPS is recommended for modern PCs with active power factor correction power supplies. Stepped or simulated waveforms can cause some of these power supplies to shut down or hum on battery. Check your power supply documentation if you are unsure.
What size UPS do I need for a desktop computer?
Choose a UPS whose watt rating is higher than your total load. Add the wattage of your PC, monitor and any router or modem, then leave some headroom. A larger rating also generally gives longer runtime, so go higher if you want more time to shut down safely.
