The National Electrical Code (NEC) outlines the guidelines concerning residential smoke detectors. Determining the appropriate smoke detector, where it should be placed in the home and what kind of power will operate it are covered in the NEC.
Placement of Smoke Detector
The NEC takes its guidelines for smoke detectors from the National Fire Protection Association (NFPA). In single-family or multifamily homes, smoke alarms shall be placed inside each sleeping area, outside each sleeping area and on each level of the dwelling. Smoke alarms are not required in unfinished attics, unfinished basements or kitchens.
Power Supply
Each smoke detector in the home must be wired together by low-voltage electricity running throughout the dwelling, according to the NEC. This is so that if one alarm sounds, all the alarms sound. The NEC permits battery-operated smoke alarms in older homes that weren't wired for smoke alarms.
Types of Smoke Alarms
The NEC says either of two types of smoke alarms are acceptable for homes. There is the ion type, which sounds more quickly when flames are detected and is the cheapest type. The second type recommended by the NEC is the photoelectric type, which sounds more quickly in the presence of smoke particles, but is not as sensitive to cooking smoke as the ion type.