Power cuts and voltage swings are the most common reason we find a camera system with gaps in its recording. The cameras are fine; the recorder rebooted, or its hard drive was damaged by a surge when the power came back. A few decisions at install time prevent almost all of it.

Put the recorder and the switch on a UPS

The NVR and the PoE switch that powers the cameras are the heart of the system. If both sit on a UPS, every camera keeps recording through a cut. A line-interactive UPS is fine for short outages; for sites with poor power quality, an online (double conversion) UPS gives the recorder clean power all the time, not just during a cut.

Size it for the load and the time you need:

  • Add up the wattage of the NVR, the PoE switch and any cameras powered separately.
  • Decide how long you need to record without mains: 30 minutes covers a changeover to a generator, several hours needs extra battery or solar.
  • Leave headroom. A UPS running at 90% of its rating gives much less runtime than the brochure suggests.

Protect against the surge when power returns

The dangerous moment is often not the cut but the return, when voltage can spike. Use a surge protector or automatic voltage regulator ahead of the UPS, and surge protection on long outdoor cable runs, which also pick up lightning-induced surges in the rainy season.

Use PoE so one UPS powers everything

Power over Ethernet sends power to each camera down its network cable. It means one UPS behind the switch keeps every camera alive, instead of a separate adaptor per camera that dies with the local socket.

Consider solar for remote poles

Cameras at the far end of a yard or fence often have no dependable mains at all. A small solar panel, charge controller and battery per pole, with wireless back to the recorder, is now a routine installation.

Check it, do not assume it

Batteries wear out, typically within a few years in our heat. Once a quarter, switch off the mains deliberately and confirm the system keeps recording. Look at the recorder's event log for unexplained reboots; each one is a gap in your footage.