Which type of installation is NOT permitted for non-metallic boxes?

Non-metallic boxes are designed with specific applications in mind, primarily focusing on conditions where they can maintain structural integrity and safety. Among the options provided, installations in areas where high physical damage is likely are not permitted because non-metallic boxes lack the durability required to withstand significant impact or mechanical stress.

In environments susceptible to physical damage, such as industrial settings or areas where equipment may come into contact with the box, a more robust enclosure is needed. Metal boxes or other reinforced materials are typically appropriate in such circumstances as they offer better protection and prevent damage to the wiring and connections housed within.

Other scenarios mentioned, such as outdoor applications in mild climates, indoor residential use, and installations in low moisture environments, are suitable for non-metallic boxes. These conditions allow the non-metallic materials to function effectively without the risk of deterioration or failure, making them suitable for standard residential and mild outdoor applications.