Keeping CCTV Recording During Power Cuts: Inverter and UPS Guide

Why power backup is not optional

Power cuts are still a fact of life in many parts of Bangalore, especially in industrial areas and during the monsoon. A CCTV system without backup goes blind at exactly the moments when it is most needed — and intruders know when the area is dark. Repeated sudden shutdowns also damage hard disks, a leading cause of lost recordings.

What needs backup

• The recorder (DVR or NVR) — always.
• The cameras — via their power supply (HD analog) or the PoE switch/NVR (IP cameras).
• The router or internet modem, if you want remote viewing and alerts during a power cut.
• The monitor is optional — recording continues without it.

Estimating the load

Most fixed cameras draw a few watts each, rising at night when IR or white lights switch on. A small recorder draws tens of watts. As an example, eight cameras at around 6 W each plus a recorder at about 20 W is roughly 70 W. PTZ cameras and long-range IR cameras draw much more — check datasheets and add them separately. Size the backup for the night-time peak with some headroom.

Worked example

A home with eight IP cameras on a PoE NVR: each camera draws a few watts, more at night with infrared on — say up to about 6 W each, or roughly 50 W for eight. The NVR with a hard disk might draw around 20–30 W, and the router about 10 W. Total: roughly 80–90 W. A small online UPS or a home inverter can carry this for hours; a basic computer UPS will last only minutes at this load. Check the actual figures on your equipment datasheets.

Inverter or UPS?

How we usually set it up

For homes and small offices, we connect the recorder and camera power supply to the existing inverter circuit. For businesses and larger systems, the recorder, PoE switches and network equipment sit together in a rack on a UPS, often itself supported by the building’s inverter or generator. Centralising power at the rack — which IP and PoE systems make easy — means one backup covers every camera.

Protect against surges and low voltage

• Fit surge protection for the recorder and camera power supply; voltage spikes when power returns are a common cause of failures.
• Use surge protectors on long outdoor cable runs and pole-mounted cameras.
• Make sure the earthing at the site is sound.
• In areas with frequent low voltage, a stabilised supply or online UPS protects equipment.

Test it

Switch off the mains briefly and check that the recorder and every camera stay on, including at night when the IR is on. Then check that remote viewing still works if you backed up the router.

Generators and changeover

Apartments and factories often have diesel generators, but there is usually a gap of seconds to a minute before the generator takes over. Without a UPS, the recorder reboots and cameras drop out every time. A UPS bridges this gap so recording continues without interruption, and protects equipment from the voltage spikes that can occur during changeover.

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