What is a requirement for the installation of thermal cut-off switches?

A thermal cut-off switch is designed to automatically shut off a system when it reaches a predetermined temperature, which is crucial for safety measures in heating equipment. The requirement that it must be located at the highest point above the unit ensures that the switch can accurately monitor the temperature of the system and respond to overheating conditions effectively. Positioning it at the highest point allows the switch to detect any rise in temperature that may occur, as heat rises. This placement helps to prevent potential hazards such as overheating or fires.

Other options may suggest accessibility or operational features that do not align with the primary function and safety requirements of thermal cut-off switches. For instance, while ease of access might be important for maintenance, the critical aspect is that the cut-off switch is correctly placed to serve its protective purpose.