A:Answer Use a battery backup system (UPS) to power and protect the security system. It keeps everything running 24/7 or until the UPS battery runs out. The APC 1500 VA unit, for example, can run for 170 minutes. The load current determines run time.
Security systems often have an interesting failure mode. If a camera fails, the DVR might continue showing the last image. As a result, you may never see a troublemaker if he or she destroys a camera. Test this by watching all cameras working and then disconnect power to one. See if a black screen or last image gets recorded.