replacing smoke detectors

[Jud McCranie]

Two years ago I replaced the smoke detectors downstairs, today I did it upstairs. The new detectors have black, white, and red wires, and can be interconnected so that if one goes off, they all sound off. The old detectors upstairs had black, white, and yellow wires. The box has black and white wires and a bare wire. The yellow wire was NOT connected. (I measured 119V between the bare wire and one of the others.) I left the red wire unconnected. Would it be OK to connect the red wire to the bare wire?

[RBM]

It would not be OK. The third wire is for interconnect. You only have a feed. Keep it capped

[Jud McCranie]

Thanks, I did. The red wire came with a cap on it, and I left it on.