2 Wire Smoke Detector Wiring Diagram | Free Wiring Diagram Assortment of 2 wire smoke detector wiring diagram. A wiring diagram is a simplified traditional photographic depiction of an electrical circuit. It reveals the parts of the circuit as streamlined forms, and also the power as well as signal links between the devices. Connecting 2 Wire Smoke Detectors - Home Security Systems Connecting 2 Wire Smoke Detectors. Follow the specific fire alarm schematic supplied by the smoke detector manufacturer to make connections. A smoke detector wiring diagram is normally included with every detector, and will show you how to correctly hook up the device.