Networking manufacturers are using power supplies ranging from 5.0 to 12 VDC, with no consistency whatsoever. This issue is of great concern for security installations for a number of reasons. If using plug-in transformers, accessible non-switched AC power outlets must be located to power an IP-addressed camera, for example. Consideration has to be given to somehow protecting the plug-in transformer from being unplugged. The transformer also must be located somewhat near the camera, as the length of connection cables provided by the vendors is generally 15 ft. or less. Building electrical and fire code problems can arise if a plug-in transformer and its associated cabling are installed within a plenum ceiling. And even if a suitable, secure, and code-acceptable wall outlet is found, any power failure, brownout, or surge can either disable, destroy, or lock up the software in the device.
The very devices that provide the tremendous flexibility of networking installations are just as susceptible to power problems. Routers, switches, hubs, and cable/DSL adapters all have their own power requirements, and can suffer the same types of problems if there is a glitch in the power grid. What this means is that video or alarm signals and device communications can be lost due to power problems along the signal path.