How to Wire Smoke Detectors in a Series

You can wire smoke detectors that are installed in your walls or ceilings in a series so that all will sound an alarm when one of them detects smoke.

The procedure is straightforward, but you must disconnect the electric line that feeds power to the various rooms where the smoke detectors are located. You'll need a few tools and experience handling electric wires, along with some supplies from a hardware store.

Disconnect the power to the rooms where you have the smoke detectors by pulling the appropriate fuse or tripping the appropriate circuit breaker in the fuse box.

Place a ladder beneath one of the smoke detectors. Remove the outer part of the smoke detector from the base by turning it counterclockwise. Remove the power clip from the back of the smoke detector by pressing on the clips and pulling the connector off the back. Remove the screws holding the base to the ceiling with a Phillips screwdriver. Fish the one-time-use electric cable from the hole in the ceiling or wall back to the smoke detector's control panel.

Loosen the screws on the electrical junction box inside the hole that the base covered.

Go to the next smoke detector and repeat the same steps until you have reached the last smoke detector.

With a utility knife, make a slit in the outer insulation 4 inches from the end of the electric wire of the last smoke detector. Pull back the outer insulation and the paper insulation beneath it to reveal a set of wires. Loosen the screw on the lower right corner of the electrical junction box inside the hole in the ceiling or wall. Wrap the end of the bare (ground) wire that is inside the electric cable around the screw. Tighten the screw.

Strip 1/2 inch of insulation from the ends of the other wires using wire strippers. Wind the exposed ends of the wires just stripped around the corresponding screws on the electrical junction box: the black wire from the electric wire around the screw to which the black wire from the power clip is attached; the white wire from the electric wire around the screw to which the white wire from the power clip is attached; and the red wire from the electric wire around the screw to which the yellow wire from the power clip is attached. Wrap strips of electrical tape around each of the sets of wires.

Reattach the base to the ceiling or wall. Reattach the power clip to the back of the smoke detector. Twist the outer part of the smoke detector back onto the base.

Return to the smoke detector that you worked on prior to the last one. Cut and strip the ends of the two electric wires that are in the ceiling or wall hole in the same manner.

Attach the exposed ends of the two wires around the screws on the electrical junction box as follows: the two black wires from the electric wires around the screw to which the black wire from the power clip is attached; the two white wires from the electric wires around the screw to which the white wire from the power clip is attached; and the two red wires from the electric wires around the screw to which the yellow wire from the power clip is attached. Wrap strips of electrical tape around each of the sets of wires.

Twist the two bare (ground) wires from each electric cable around the other and cover them with a strip of electrical tape. Reattach the smoke detector to the ceiling or wall.

Continue this process until you reach the first smoke detector. Cut and strip the wiring on both ends of the one-time-use electric cable in the same manner as earlier. Connect the wiring from the electric cable to the screws on the electrical junction box in the same manner as on the last smoke detector. Reattach the smoke detector to the ceiling or wall.

Wind the exposed ends of the wires from the one-time-use electric wire around the screws as follows: the black wire around the screw labeled "Positive"; the white wire around the screw labeled "Negative"; and the red wire around the screw labeled "Grn." Tighten the screws. Restore the electric power to the rooms and smoke detectors.

Things You Will Need

  • Ladder
  • Phillips screwdriver
  • Electric cable, 12-3 NM grade
  • Utility knife
  • Wire strippers
  • Ruler
  • One-time electric cable, 12-2 NM grade
  • Control panel

About the Author

Marshal M. Rosenthal is a technology maven with more than 15 years of editorial experience. A graduate of Brooks Institute of Photography with a Bachelor of Arts in photographic arts, his editorial work has appeared both domestically as well as internationally in publications such as "Home Theater," "Electronic House," "eGear," "Computer and Video Games" and "Digitrends."