Replacing a Smoke Alarm

Is your smoke alarm more than 10 years old? Time to replace and while you are at it, I recommend you upgrade your smoke alarm to dual sensor models that have both ionization and photoelectric capabilities. Read on below for step by step instructions on how to replace an existing hardwired smoke alarm in your home. 

Old ionization only smoke alarm on the left. Newly installed dual ionization and photoelectric smoke alarm on the right.

Tools needed:
-Non contact electrical tester
-Phillips head screwdriver

Parts Needed:
-New smoke alarm - for this project I am replacing a hardwired and interconnected smoke alarm system. The parts that come in the box are a new alarm body, a ceiling bracket and a new wire pigtail with connection adapter.
​-Wire Nuts

New smoke alarm parts. Alarm body in upper left. Ceiling bracket on right. New wire pigtail with connection adapter on the lower left.

These directions are specific to to replacing a hardwired (connected to household AC current) and interconnected smoke detectors. If you don't feel comfortable working with electrical wires consider having a qualified party do this work. 

1. Turn off the circuit breaker controlling the circuit for your fire alarm.

2. Remove the existing smoke alarm from the ceiling bracket.

​3. Test at the smoke alarm wire pigtail to ensure that the power is off.
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Step 1: Turn off the circuit breaker feeding your smoke alarm circuit. Step 2: Remove the existing alarm from the ceiling bracket.

Step 3: Testing the circuit. This one is still live as indicated by the red light on the tester.

Step 3: Correct circuit breaker has been turned off. Tester now shows green meaning no power in the wire.

Step 4: Remove the pigtail wires from the back of the smoke alarm.

​Step 5: Loosen the screws holding the existing bracket to the ceiling junction box. Remove the bracket.

Step 4: Remove the pigtail bracket from the back of the alarm. You may have to squeeze tabs on the side of the bracket to remove.

Step 5: Loosen the screws and remove the existing bracket from the ceiling. It may take a little effort if the ceiling paint has adhered to the back of the bracket.

Step 6: Pull the existing wires out of the junction box. There should be a black wire, white wire and a red wire in the box. The pigtail connection to the alarm will have a black wire, white wire and either a red or orange wire. Remove the wire nuts and separate the old pigtail from the ceiling wiring.

Step 7: Match up the pigtail connector wiring to the existing house wires. Black attaches to black. White to white wire and Red or orange to red.
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​Step 8: Make a connection between the pigtail wires and the house wires using a wire nut. Make sure that the wire colors match.

Step 6: Pull the wire connections out of the junction box. Once free, remove the wire nuts from each connection to release the old pigtail wires.

Step 7: Match the wires. Black to black. White to White. Orange or Red on the pigtail to red in the junction box.

Step 8: Connect the pigtail to the matching wires from the junction box. Secure the connections with wire nuts.

Step 9: Tuck the house wires and connections back in to the junction box. 

Step 10: Thread the pigtail connection through the ceiling bracket.

Step 11: Secure the new ceiling bracket to the junction box and ceiling by replacing and tightening the screws that were loosened in step 5.

Step 9: Clean up the wires by tucking them back in to the junction box.

Step 10: Place the smoke alarm pigtail through the ceiling bracket.

Step 11: Secure the ceiling bracket to the junction box. Leave the pigtail hanging.

Step 12: This step is optional but highly recommended. Write the date of installation for both the battery and smoke alarm prior to installing in the bracket. This will make it easy in the future to know when the battery and alarm need to be replaced. 

Step 12 (Optional): Mark the battery with the date of install. Easy to keep track of when to change it next year.

Step 12 (Optional): Mark the smoke alarm body with date of installation. Helps to track life expectancy (10 years from this date).

Step 13: Connect the pigtail adapter to the back of the smoke alarm.

Step 14: Gently place the pigtail in to the junction box while seating the smoke alarm body. 

Step 13: Attach the pigtail adapter to the smoke alarm body.

Step 14: Push the pigtail in to the junction box while seating the alarm body in the ceiling bracket.

Step 15: Seat the alarm body in the bracket. Twist to seat. You may have a ribbon to pull to activate the alarm. Pull gently and steadily to remove the ribbon and activate the alarm. 

Step 16: Cover your ears and push the test button to make sure that the new alarm works.

Step 15: Seat the alarm and twist to secure.

Step 15: Pull gently and steadily on the activation ribbon (if present) to remove.

Step 16: Push the test button to see if the alarm works. This is an interconnected system so activating this alarm should activate all the other alarms in the house.