How to Hardwire an 120V AC Wire in a Kidde Combination Smoke & Carbon Monoxide Alarm

UTC Fire and Technologies Company manufactures Kidde brand smoke and carbon monoxide detectors. Available models continuously monitor for smoke, carbon monoxide, or both, and sound an alarm upon detecting either substance in the air. Some models operate only on batteries, while others use the house current with a battery backup. Models that use 120 volts interconnect with other units in the house, and if one is triggered, the alarms on all interconnected units sound.

No-contact voltage tester
Screwdriver
Green ground screw
Wire stripper

Instructions

- 1
  Turn the back-plate on the smoke and carbon monoxide detector to remove it from the rest of the unit. It will only turn one way. The unit connects to the house wiring with a plastic connector. Grasp the unit with one hand, the connector with the other hand, and carefully pull it apart to separate the alarm from the wire connector. Do not grasp the wires to pull it apart.
- 2
  Turn off the circuit breaker that controls the circuit for the smoke/CO alarm. Bring the no-contact voltage tester close to the wires. If the light remains off, the wiring is safe to work on.
- 3
  Pull the wires out of the wiring box so they hang down. If the wiring box is metal, and there is a bare ground wire in the box, screw a green ground screw into a threaded hole in the back of the box, wrap the bare ground wire around it, and tighten the screw firmly.
- 4
  Feed the wires through the hole in the alarm's back-plate that was just removed from the alarm. Screw the back-plate to the wiring box using the screws provided with the wiring box. Do not over-tighten the screws, or the back-plate may crack or break.
- 5
  Strip 1/2 inch of insulation from each house wire with the wire stripper. Hold the bare end of the white house wire together with the bare end of the white alarm wire. Place a supplied wire nut over the two wires, and turn it clockwise until it is tight. Repeat this step for the black house and alarm wires.
- 6
  Connect the yellow alarm wire to the colored house alarm interconnection wire in the same way as the other wires. Common interconnection wire colors are red, yellow and orange, but according to the National Electrical Code may be any color except green, white or natural gray.
- 7
  Push the plastic wire connector onto the smoke alarm terminals. The connector only fits one way. Fit the alarm onto the back-plate, and turn it to connect the alarm to the back-plate. Turn on the circuit breaker, and press the test button. The alarm should sound if it is wired correctly.

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