The Importance of Reading Directions

This post could also be called 'Pay Attention, Especially if You Think You Know What You're Doing.' (Clearly I managed to make a mistake of some sort.)

First a bit of background. In the fire alarm / low voltage world wiring isn't usually a hot, a neutral and a ground. Wiring is almost always only a positive and a negative. The rule for wire identification is that the darker (usually black) is negative and the lighter wire (usually red) is red.

The fire alarm system I'm installing has MANY components, but the problem revolved around the speakers and the combination speaker/strobes. The speakers have two terminals on the back with a brown lead and a white lead leading away from the terminals. The speaker circuit is a blue cable consisting of on red #16 wire and one black #16 wire. Logic dictates that the red wire (the lighter one) goes under the white terminal and the black wire (the darker one) goes under the black terminal. And, lucky for me, that turns out to be the correct way to wire the speaker.

The combination speaker/strobes have four terminals on the back, two (red & black) for the strobe and two (white and brown) for the speaker. The circuit for the strobe is two separate #14 THHNs with the light/dark color combinations depending upon which circuit the strobe is a part. The red and black terminals are labeled "S" for strobe and the wires are landed exactly how you'd expect. The speaker terminals, again white & brown, however, are NOT what you'd expect. After installing more than 50 of these, I noticed that there was something molded into the plastic beside the speaker terminals. The brown terminal was labeled 'SPKR' and the white terminal was labeled 'C' for common. In the low voltage world the negative (darker) wire is used as the common wire.

The two devices are from the same manufacturer. Each on has a speaker component. Each speaker is fed from a brown and white terminal. Except the color's polarities aren't consistent.

At least my foreman was understanding.

So, after that long and boring story, the root: I installed all of the speaker/strobes incorrectly because I put the darker speaker wire under the darker terminal. The moral of the story being that no matter how straight forward you think a task is, pay attention and read the directions.