Rack-mount UPS units are uninterruptible power supplies built for 19-inch cabinets, used in server rooms, network cabinets and small data rooms. Our range has over 270 models, including APC, CyberPower, Eaton and Vertiv. Some units can be fitted in a rack or stood upright on the floor, so the same model can suit either setup.
How to choose a rack-mount UPS
Topology. A double-conversion (Online) UPS powers your equipment continuously through an inverter, so there is no switchover when the mains fails, which matters for servers and storage. Line-interactive models cost less, regulate the voltage and move to battery within a few milliseconds. Our range includes both types, while the simplest Standby (Offline) design is rare.
Power rating. Add up the power draw of the equipment in watts and compare it with the UPS rating in W, not only in VA. Leave some headroom, so that adding a server or switch later does not push the UPS to its limit.
Battery and runtime. Most models use sealed lead-acid (VRLA) batteries, some use lithium-ion (Li-Ion), and a few use lithium iron phosphate (LiFePO4). Lithium batteries are generally lighter and last longer, but the UPS costs more. If you need a longer runtime, check whether the model accepts extra battery modules.
Height and form factor. Rack units are measured in rack units (U), so check the free space and the depth of your cabinet before buying: a UPS with batteries is heavy and deep. Our range includes Rackmount, Tower and Rackmount/Tower models, and the last group works both in a cabinet and standing upright.
Outlets and connection. Most models offer C13 outlets, which servers, switches and other IT equipment with a standard power cord use. Some also have C19 outlets for more demanding equipment, and a few of the largest units need terminal blocks or a hard-wired connection to the mains.
Brands in our range
- APC: the largest brand in our range, known for the Smart-UPS series made for server cabinets.
- CyberPower: makes both line-interactive and online rack models, so you can match the unit to a network cabinet or a server.
- Eaton and Eaton Powerware: Eaton acquired the Powerware UPS business, so the two names are linked; Eaton is known for its 5P and 9SX rack UPS series.
- Vertiv: formerly part of Emerson Network Power, known for the Liebert UPS line used in server rooms and data centres.
- BlueWalker and PowerWalker: PowerWalker is the UPS brand of the German company BlueWalker.
Also in our range: ROLINE, Online USV-Systeme, Qoltec, Energenie and Digitus.
Frequently asked questions about rack-mount UPS
What is the difference between Online and line-interactive rack UPS?
An Online (double-conversion) UPS feeds equipment through an inverter all the time, so there is no switchover to battery, while a line-interactive model switches over in a brief moment. Online suits sensitive equipment such as servers, whereas line-interactive is often enough for network cabinets and small offices. Online models usually cost more.
What UPS rating does a server need?
Add up the power draw of all connected devices in watts and choose a UPS whose rated power in W is higher than that total. VA shows apparent power, and the real load depends on the power factor, so check both figures. It is sensible to leave headroom for future expansion.
Can a rack UPS be used outside a rack?
Yes, if the model is listed as Rackmount/Tower, it can be fitted in a cabinet or stood upright. Pure Rackmount models are designed for cabinets and are heavy, so they are best fixed on rails.
Which battery is better in a UPS: VRLA or lithium?
Lithium-ion and LiFePO4 batteries generally last longer and weigh less than VRLA, but such UPS units cost more. VRLA is the most common battery type in our range, and worn batteries can be replaced with new ones. For everyday office or network cabinet use, VRLA is often enough, while lithium makes sense when low weight and less frequent battery replacement matter.
