How do I choose a UPS for security camera systems?

A camera system usually includes the recorder (NVR or DVR), the cameras, a PoE switch if the cameras are powered over the network cable, and often a router or modem. To calculate the load, add up the consumption of each device from the labels or datasheets. With PoE cameras, what mainly counts is the switch consumption, which includes the power of the cameras. Cameras with infrared illumination draw more at night, so calculate with the maximum value.

Example: if the total is 200 W, with a 30% margin you need about 260 W. Because UPS units state their capacity in both VA and W, check that the W rating is also sufficient. Runtime is just as important: a security system must keep recording during the outage, so you may need more battery capacity or a model that accepts external batteries.

Practical tip: recorders run around the clock with hard drives, so prefer a pure sine waveGlossary · UPS technologyPure Sine WaveUPS output with the same waveform as the mains, needed for PFC power supplies, motors and sensitive equipment, unlike a stepped approximation. UPS and, where possible, set up a controlled shutdown of the NVR before the battery runs out. A common mistake is forgetting the router and switch, so the cameras keep recording but remote access is lost.