What does Article 410 state regarding the mechanical stability of luminaires?

Article 410 emphasizes the importance of mechanical stability for luminaires, which means that they must be securely installed in a way that ensures they remain stable and safe during operation. This stipulation is essential because luminaires can be subjected to various conditions such as vibrations, temperature changes, and physical interactions that could compromise their stability if not properly secured.

The requirement for mechanical stability helps to prevent hazards such as fixture failure, which can lead to lighting outages, potential damage to property, or even physical injury. Thus, luminaires must be designed and installed to withstand these conditions while maintaining their position and function.

The other choices lack compliance with the NEC's intent on safety and stability. Installing luminaires in any manner without regard to their stability could lead to unsafe conditions, while not requiring any stability measures ignores the practical realities of the environments in which luminaires are used. Also, the idea of installing luminaires loosely contradicts the need for them to be securely fastened to avoid potential risks.