How to Install a Firex Hardwired Smoke Detector

Install a junction box to accept the smoke detector on a ceiling joist, in new construction. In existing construction, cut an opening in the ceiling drywall from one ceiling joist to the next and install a ceiling fan brace with its built-in junction box between two joists. Screw the drywall back in place, with drywall screws holding the piece to the joists, with an opening cut to the shape of the junction box.

Flip off the breaker or breakers that control power to the room you are working on. Fish a length of 14-guage electric wire from an unassigned 15-amp circuit on your electrical panel to the junction box.

Pull the wire through the center of the mounting plate. Secure the mounting plate of the smoke detector to the junction box with mounting screws.

Connect the black wires, white wires and ground wires in the junction box to the corresponding wires in the smoke detector’s connecting plug, using wire nuts. Press the connector plug onto the pins on the back of the alarm. Press the alarm against the mounting plate, and turn it clockwise to lock it into place.

Turn on the 15-amp circuit controlling the smoke detector. Test the alarm by pressing the “smart button” in the middle of the device until the yellow light flashes. Activate the battery as a backup by pulling off the plastic arrow tab and closing the battery door.