How to Connect Smoke Alarms

Run a 15-amp dedicated circuit from the electrical panel to the site of the first smoke detector. Then run a length of three-wire cable (black, red and white) from the first smoke detector's location to the second, from the second to the third and so on.

Pull the two lengths of wire into the old-work drywall box where the first smoke detector will be located. Install the box in the ceiling. Cut away the excess wire, leaving about 6 inches of each hanging outside of the box.

Strip away the outer sheath of insulation on both sets of wire to reveal the individual strands of wire. Then use the wire strippers to remove about 3/4 inch of insulation from each wire.

Take the wiring module from the first smoke detector and connect the two black wires in the junction box to the black wire on the wiring module. Follow the same procedure for the white wires. Then connect the red wire in the junction box to the yellow (or red) wire on the wiring module.

Install the smoke detector as recommended by the manufacturer.

The wiring for each smoke detector after the first one will be the same--black wires connected together, white wires connected together and the yellow (or red) module wire connected to the red wires.

Upon completion, turn the circuit on and insert a new backup battery in each smoke detector.

Press the "Test" button on one of the smoke detectors and, if wired properly, they should all ring.