LIM Function — FRCA Primary MCQ
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Correct answer: A — Monitors the potential current that would flow to earth if a fault occurred in the isolated power supply
The LIM continuously monitors the impedance between each power line and earth. It calculates the potential fault current that would flow to earth if a ground fault occurred. It alarms (typically at 2-5 mA) warning of insulation breakdown before a dangerous current can flow. It does not disconnect the power — this would interrupt life-support equipment.
Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment