Question 203Electricity & Electronics - Assistant Engineer

The correct answer is D) bimetallic snap-disc. Bimetallic snap-disc detectors are the only type of fixed temperature heat-actuated fire detectors listed that can be reused after detecting a fire. This is because the bimetallic element in these detectors will snap back to its original position once the high temperature condition is removed, allowing the detector to be reset and reused. The other options, such as liquid expansion, thermostatic cable, and fusible metal detectors, are one-time use devices that are destroyed or damaged when activated by heat, and cannot be easily reset or reused after a fire event.