NCIDQ IDFX Practice Exam

A fail-safe feature in an electric lock is designed to enhance safety, particularly during situations such as a power failure. In this context, when the power fails, the primary function of a fail-safe lock is to ensure that people can exit the premises without obstruction. By retracting the bolt, it allows individuals to leave safely and promptly, which is crucial in emergencies where quick evacuation is necessary. This design prioritizes human safety over security, acknowledging that in certain situations, allowing exit is more critical than keeping the door secured.

The other options do not align with the purpose of a fail-safe feature. For example, if the door were to remain locked during a power outage, it would pose a significant safety risk. Similarly, making the key ineffective does not serve any safety purpose in a power failure, and the idea of a lock catching fire is not relevant to the functionality of fail-safe features in electric locks. Such features are fundamentally built around the principle of ensuring safety and accessibility rather than enhancing security in emergency scenarios.