They cost a little extra and require more effort to install, but hard-wired smoke detectors are fast becoming a popular product with homeowners. Many states now require them for all new homes. You can install hard wire smoke detectors on ceilings or from the attic.
Choose wall or ceiling locations for the smoke detectors within your home. Use a utility or reciprocating saw to cut holes for each smoke detector.
Pull the cables through the holes within the smoke detector. Use a two-wire cable through the first hole and three-wire cables through every other hole. Use the multipurpose tool to install a cut-in box and put the cables within the box.
Take a cable ripper and strip the insulation and sheathing off the cables. Locate all of the wires within the cut-in box by color. Bring together the black wires, white wires and ground wires. Use wire connectors to bind them.
Attach the red wire within the three wire cable to the smoke detector's yellow wire. Fish the wires through the wiring module on the smoke detector. Install the wiring module on a mounting plate on the ceiling.
Inspect all appliances and electrical equipment before beginning any installation job. Unless the manufacturer's directions specify an appliance is safe to use in wet areas, never use electrical equipment near water.