A smoke detector is a small electronic device that sounds an alarm when it detects smoke, excessive dust or heat. A smoke detector installed into each room in your home can greatly increase you and your family’s chances of escaping unharmed in the event of a fire. Smoke detectors can be wireless or hard-wired to your home's electrical system. The advantage of a battery-powered wireless smoke detector is that an electrician is not needed to provide wiring to power the device. However, although a hard-wired detector may use batteries as a backup in case of a power failure, you will not have to worry about the detector not working because of dead batteries.
Turn off the circuit breaker that powers the electrical circuit for your smoke detector wiring at the main electrical box. Test the wires with a no-touch electrical tester to ensure the correct breaker has been turned off before proceeding.
Remove the mounting plate from the backside of the smoke detector by pulling it gently away from the device until it pops off. Feed the black and white wires from your home's electrical box where the detector will be mounted through the centre hole in the mounting plate. Hold the mounting plate to the electrical box. Line up the mounting holes and thread the screws that came with the box through the mounting plate and into the box. Tighten the screws with a Phillips screwdriver.
Hold the smoke detector near the mounting plate. Twist the white wire from the electrical box and the white wire from the smoke detector together with a pair of pliers. Twist a wire nut onto the twisted wires in a clockwise direction until it is tight.
Twist the black wire from the electrical box and the black wire from the smoke detector together with a pair of pliers. Twist a wire nut onto the twisted wires in a clockwise direction until it is tight.
Push the smoke detector gently onto the mounting base until it snaps into place. Turn the circuit breaker back on at the main electrical box.
Interconnecting smoke detectors will cause all detectors to sound even if only one unit detects smoke. If you are in interconnecting smoke alarms, connect the yellow wire from the smoke alarm to the wire that connects the yellow wires from the other smoke alarms. Use 18-gauge wire to connect smoke alarms that are less than 457 metres (1,500 feet) apart. Use 14-gauge wiring to connect smoke alarms that are up to 1,220 metres) (4,000 feet) apart. If you are not interconnecting you detector, wrap the end of the yellow wire with electrical tape.