Server Room UPS: Sizing, Supply and Service
A server room UPS has one job: carry the IT load long enough for an orderly shutdown or a generator start, every time, without drama. Getting there is a sizing exercise, a topology decision and a battery plan. This page walks through all three for the rooms Canadian organizations actually run, from a single cabinet to a few dozen kilowatts.
Where the UPS sits in the room
A small-room one-line: the UPS carries the racks and the network stack through the PDU; a generator, where one exists, picks up the long outages.
Sizing from the real load
Read the load from rack PDUs if you have them, or sum equipment nameplates. Add 20 to 25 percent headroom for growth and inrush. A one-cabinet room with a couple of servers, storage and networking commonly totals 2 to 5 kW; rooms with four to ten racks run 10 to 40 kW. Runtime targets divide cleanly: 5 to 10 minutes for shutdown or generator bridge, 30 minutes or more where staff must keep working through outages, which usually means external battery cabinets.
Topology and format by room size
Under roughly 10 kVA, online double-conversion rack units (APC Smart-UPS On-Line, Eaton 9PX, Vertiv GXT5, Tripp Lite SmartOnline) do the work and live in the cabinet they protect. Above that, compact three phase systems (Vertiv ITA2, Eaton 93PM at small frame sizes, Xtreme Power Conversion three phase models) with an external battery cabinet are easier to scale and service. The topology choice itself is settled for compute loads: online double-conversion; the reasoning is on the double-conversion page.
Batteries decide your reliability
Most server room outages we attend trace to batteries past their service life, not to UPS electronics. VRLA strings are rated around 25 degrees Celsius and give 3 to 5 years in a conditioned room; heat above that shortens the window. Impedance testing during an annual preventive maintenance visit finds weak cells before they matter, and planned battery replacement costs a fraction of an emergency one.
Supply, installation and one point of contact
GDF Technologies supplies the platforms above, installs with licensed electricians, commissions with a load and transfer test, and services the result across Canada under one contract, one report format and one phone number: 514-252-8324. For stocked equipment and replacement batteries with published specifications, browse UPS Plus Battery. Use the runtime calculator to turn your load into backup minutes per model.
Estimate your room load
Common questions
Sum the IT load in watts from the rack PDUs or equipment nameplates, add 20 to 25 percent headroom, then decide runtime: 5 to 10 minutes covers an orderly shutdown or a generator start. A single-rack room often lands at 3 to 6 kVA; multi-rack rooms move into 10 to 40 kVA where compact three phase systems take over.
Under roughly 10 kVA, rack-mount online units keep everything in the cabinet. Above that, a standalone tower or compact three phase system with an external battery cabinet is easier to service and scale, and it stops consuming rack units you need for compute.
They need a conditioned room. VRLA batteries are rated around 25 degrees Celsius; sustained heat above that shortens service life substantially, which is why the battery cabinet belongs in the cooled space, not the storage closet.
More UPS formats
One room, one point of contact
Supply, installation, batteries and the maintenance visit that keeps the room honest. Tell us what is in the racks and you get a written proposal.
