BlogPower & facilities
Online vs line-interactive UPS: choosing the right type
By David Otieno, Senior ICT Consultant 1 min read
The UPS topology determines how well equipment is protected from unstable power. Match the type to the equipment and the supply.
All UPS units keep equipment running when the power fails. They differ in how they handle everything else: sags, surges, noise and frequency variations.
Standby (offline)
The load runs on mains power, filtered, until the supply fails, then switches to battery. It is economical and suits individual desktops and small home-office equipment.
Line-interactive
Adds automatic voltage regulation, correcting moderate sags and surges without switching to battery. A good fit for network cabinets, small servers and offices with reasonably stable power.
Online double-conversion
Continuously converts incoming power to DC and back to clean AC, so connected equipment is isolated from the supply. There is no transfer time when power fails. It is the usual choice for server rooms, medical and laboratory equipment and sites with unstable mains or generator power.
Other things to check
- Capacity in both watts and VA, with headroom.
- Runtime at your actual load, from the manufacturer's charts.
- Network management card for alerts and automatic shutdown.
- Battery replacement cost and availability.
See our power and smart facility solutions.
About the author
David Otieno
Senior ICT Consultant
David Otieno writes about cybersecurity, physical security systems, power resilience and running IT reliably day to day.