NATE Air Conditioning and Heat Pumps Practice Exam

Which safety device is essential in preventing overheating in electric heaters?

1. Thermostat

2. High-limit switch

3. Fusible link

4. Current sensor

The correct answer is: High-limit switch

The high-limit switch is essential in preventing overheating in electric heaters because it is designed to interrupt the power supply when the temperature rises above a specific threshold. In the context of electric heaters, excessive heat can lead to potential hazards, including fires. The high-limit switch acts as a crucial safety feature, ensuring that the heater operates within safe temperature limits. If the heater exceeds the maximum temperature set by the high-limit switch, it will automatically shut off the heating element, thereby protecting the unit and surrounding environment from heat-related damage. While thermostats, fusible links, and current sensors play roles in managing heating systems, they do not specifically function as fail-safes against excessive temperature conditions in the same way that the high-limit switch does. Thermostats regulate temperature but do not necessarily prevent overheating on their own, while fusible links function as a thermal fuse, providing a different type of safety measure. Current sensors monitor electrical flow but may not directly address overheating issues. Hence, the high-limit switch is the most effective device for this specific safety concern in electric heaters.