2 Wire Systems

2 Wire systems provide advantages to both the installer and the building owner; they reduce the amount of cabling required to be installed and therefore provide cost savings for both materials and installation costs. The diagrams below show how a standard fire alarm system is wired compared to a 2 Wire system and how it simplifies the installation.

2 Wire CIE
This diagram illustrates a mixture of alarm, detection and input devices on the same pair of cables, hence the term ‘2 Wire System’. Fire detection devices (such as heat and smoke detectors, call points) and fire notification devices (such as sounders and visual indicators) that are approved for 2 wire compatibility can be installed on the same pair of wires.

Standard Fire Alarm CIE
This diagram illustrates a standard conventional installation. The smoke / heat detectors and call points are installed on one pair of cables and the sounders and visual indicators are installed on a separate pair of cables.