How to Change an Alarm

Trip the circuit breaker at the fuse box so that electricity is no longer running to the area where the defective smoke alarm is located. Plug a table lamp into a wall outlet in the area. Try turning the table lamp on to confirm that there is no electricity.

Place a ladder beneath the ceiling-mounted smoke alarm. Remove the screws from around the alarm with a Phillips screwdriver.

Pull the smoke alarm's mounting plate -- and the smoke alarm attached to it -- from the ceiling. Stretch the wires coming out of the ceiling so that you can access the screw-tab connectors that are on the wires.

Twist off the screw tab connectors from the wires. Place the connectors in your pocket to use later. Unwind the wires from the hole and from the back of the smoke alarm from each other. Remove the smoke alarm and place it on a work surface.

Twist the top of the smoke alarm off. Remove the battery from the battery compartment inside. Place the replacement smoke alarm on the work surface. Twist the top of the replacement smoke alarm off. Place the battery into the battery compartment and twist the top back on.

Run the wires from the ceiling through the hole in the center of the replacement smoke alarm's mounting plate. Place the mounting plate against the ceiling, over the hole. Screw wood screws through the pre-drilled holes in the mounting plate and into the ceiling using the Phillips screwdriver.

Insert the wire plug that comes with the replacement smoke alarm into the slot on the back of the smoke alarm; if the wires are permanently attached to the back of the smoke alarm, ignore this step.

Twist the end of the black wire ("hot") from the hole around the end of the black wire from the smoke alarm; twist the white wire ("neutral") from the hole around the end of the white wire from the smoke alarm; twist the copper-colored wire ("ground") from the hole around the end of the copper-colored wire from the smoke alarm. Twist the end of the yellow wire ("alarm interconnection") from the hole, if one is present, around the end of the yellow wire from the smoke alarm -- if there is no yellow wire in the hole, wrap a strip of electrical tape around the end of the smoke alarm's yellow wire.

Twist a screw-tab connector, taken from your pocket, around each of the twisted pairs of wires. Push the wires back into the hole.

Place the replacement smoke alarm against the mounting plate. Twist the alarm onto the plate with a clockwise motion. Restore the electricity at the fuse box.

Press the "Test/Reset" button on the side of the replacement smoke alarm once so that the horn sounds for a few seconds before shutting off. Place the ladder and table lamp away.