This device is designed to detect over current/short circuit and isolates the supply to its output. At the time of short circuit, the device will disconnect the supply to the consecutive series of devices connected after isolator module. Short circuit isolators are placed between groups of devices. It minimise the damage due to the short circuits. It deactivates only disturbed circuit devices and other devices are undisturbed to deliver its function.

Principle of Operation of a Short Circuit Isolator:

1. Continuous Monitoring:
   • The short circuit isolator continuously monitors the current and voltage levels in the communication loop of the fire alarm system.
2. Detection of a Short Circuit:
   • If a short circuit occurs in the loop (e.g., due to damaged wiring or a faulty device), the current in the loop increases dramatically, or the voltage drops.
3. Isolation of the Faulty Section:
   • Upon detecting a short circuit, the isolator immediately acts to isolate the affected section of the loop.
4. Restoration to Normal:
   • Once the short circuit is resolved (e.g., after repair work is completed), the isolator automatically resets itself.
5. Supervision and Feedback:
   • Some short circuit isolators provide feedback to the FACP, indicating that a section of the loop has been isolated.