Twin Wire Fire Alarm

Twin Wire Fire Alarms

Twin wire fire alarm systems are similar to a conventional system as they have detection zones. The main advantage of twin-wire systems is you can put sounders on the detection circuit which means you can save on the cost of having to wire additional sounder circuits.

How does a twin wire fire alarm work?
Each call point or smoke alarm is connected to the main fire alarm control panel by its own wire. When a detector is triggered, the fire alarm control panel will operate the sounders for a full evacuation. A twin wire system allows sounders to be installed on the circuit, meaning you don’t need to wire in additional sounder circuits.
What are the advantages of a twin wire fire alarm system?

  • Supports remote input/output interface units. So if, for example, lift control shutdown is required but the lift is sited a long way from the fire alarm control panel, the remote input/output can operate this with minimal wiring.
  • Save the cost of wiring additional sounder units
  • Reduce false alarms – the alarm is sounded only in the zone where the fire is detected. If a fire continues to be detected the alarm will sound in the whole building. If a fire isn’t detected then the system is automatically reset.
What are the disadvantages of a twin wire system?

  • Although cheaper to buy it’s more expensive to install
  • The exact location of a fire can’t be given with a twin wire fire alarm system. However, by wiring different floors or areas as zones, then an indication of which zone the fire is in can be given.
  • If a wire becomes severed, the device is disconnected and may not signal the presence of a fire.