Rack-mount UPS units protect servers, network switches and storage in 19-inch cabinets from power cuts, surges and voltage fluctuations. Our range of over 140 models covers line-interactive and double-conversion (online) units from CyberPower, APC, Eaton and Vertiv, for server rooms, small offices and branch sites with a rack.
How to choose a rack-mount UPS
Topology. Line-interactive models correct voltage variations and switch to battery during an outage, which is enough for many network racks and small server rooms. Double-conversion (online) models run the load through the inverter all the time, so there is no transfer to battery, which suits servers that cannot tolerate even a brief break. Both types are well represented in our range, alongside a single standby (offline) model.
Capacity and runtime. Add up the wattage of the equipment you want to protect rather than relying on the VA figure alone, and leave some headroom for future additions. Runtime falls quickly as the load rises, so check the manufacturer's runtime chart and look for models that accept external battery packs if you need longer.
Form factor. Rack-mount UPS units are measured in rack units (U) and are deep and heavy, so check the depth of your cabinet before ordering. Many models in our range are rackmount/tower convertibles that can sit in a rack or stand on the floor, while others are rack-only.
Outlets and connections. Most models use C13 outlets for standard IEC power cords, and many also add C19 outlets for larger servers and chassis. Some units are hard-wired through a terminal block. Outlet counts in our range run from 3 to 10, and a few units have more outlet types than a single plug standard.
Battery technology. Most units in our range use sealed lead acid (VRLA) batteries, which are the usual choice and are straightforward to replace. Some models use lithium-ion, which generally lasts longer and weighs less than lead acid.
Rack-mount UPS brands we carry
- CyberPower: has the largest number of rack-mount UPS models in our range, spanning line-interactive and online units.
- APC: a Schneider Electric brand best known for its Smart-UPS series, which is widely used in server rooms.
- Eaton: a power management company that took over Powerware, with UPS ranges common in data centres and server rooms.
- Vertiv: the company formerly known as Emerson Network Power, and the owner of the Liebert UPS brand used in data centres.
- PowerWalker: a German UPS brand from BlueWalker, offering both line-interactive and online models.
Also in our range: Qoltec, Roline, East, Online USV, IBM, Armac and ABB.
Rack-mount UPS FAQ
What is the difference between an online and a line-interactive rack UPS?
An online (double-conversion) UPS powers your equipment from the inverter continuously, so there is no switchover when the mains fails. A line-interactive UPS passes mains power through, regulates voltage, and switches to battery within a few milliseconds. Online models give stronger protection for servers, while line-interactive units are usually enough for network gear and smaller setups.
How much capacity do I need for a server rack?
Add up the power draw of all connected devices in watts, then choose a UPS whose wattage rating exceeds that total with some headroom. The VA figure is higher than the watt figure, so compare watts to watts. If you plan to add equipment later, choose a larger unit or one that supports extra battery packs.
Can I use a rack-mount UPS without a rack?
Yes, if it is a rackmount/tower convertible, which can stand upright on a floor or shelf. Rack-only models are designed to be bolted into a cabinet and are not meant to stand freely. Many units in our range are convertible, so check the form factor in the product details.
How often do UPS batteries need replacing?
Sealed lead acid batteries typically need replacing every three to five years, depending on temperature and how often the UPS runs on battery. Lithium-ion batteries generally last longer. Many rack-mount models have hot-swappable batteries, so you can replace them without switching off the connected equipment.
