WIRED SYSTEMS IN BRIEF

The six wires are basically three sets of two: a positive and negative supply to feed powered sensors; the alarm circuit feed and return; and the tamper circuit feed and return. The tamper circuit is a second, permanently on, alarm system of the sensors themselves. So, if anybody “tampers” with, or opens, a sensor – perhaps to disable it for a subsequent break in – the tamper alarm will go off, even when the alarm itself isn’t set.

PIR sensors do require power, but they’re not really recommended for workshop use. Although some are more sophisticated than others, they are the most prone to false activation – usually due to insect ingress or dramatically varying temperatures.

Door/window sensors are essentially a reed switch that is open – ie. doesn’t let current through – until a magnet is placed near it, which occurs when the door/window is shut. They don’t require a power source, so only four wires are used.

Glass-break detectors listen out for a critical frequency breaking glass gives off. If your workshop has no opening windows, then a single glass-break detector is obviously cheaper, and easier to install, than several vibration detectors. The wiring itself is simple. The power lines are connected in parallel, so the alarm panel’s positive is connected to all the powered sensors’ positives. The alarm and tamper circuits, in contrast, are giant daisy chains. The alarm’s output goes to the first sensor’s input, then that sensor’s output goes to the next sensor’s input. This continues all the way back to the panel’s return connection.