R314.6

Section R314.6 is titled 'Power source' and covers requirements for devices which detect and warn of smoke accumulation. The requirement for a smoke alarm to be powered from the dwelling's primary power source, to have battery backup in the event of primary power loss, and to not have any switching mechanism in the primary power circuit, excepting for overcurrent protection is established. The purpose of this section is to assure smoke alarms will always have power with minimal maintenance. This section has 2 exceptions which exempt the requirement for a commercial power source in certain situations. The purpose of these exceptions is to allow for battery power only devices to be installed where there is no commercial power, or the ability to run commercial power to devices is not practical.

The model shows a smoke alarm being (diagrammatically) fed from a circuit breaker panel.