What must be ensured regarding the power supply to fixtures under Article 410?

The requirement that the power supply must be adequately rated for the number and type of luminaires is key under Article 410 of the National Electrical Code (NEC). This ensures that the electrical system can handle the load imposed by the luminaires without overloading the circuit, which could lead to overheating and potential fire hazards. Each luminaire has a specific wattage or power requirement, and the total load of all luminaires on a circuit must not exceed the rating of that circuit, ensuring compliance with safety standards.

This rating considers factors like the voltage, current, and types of luminaires being used — for instance, LED fixtures versus incandescent lights have different power requirements. Properly rating the power supply also contributes to energy efficiency and ensures that the fixtures operate at their designed performance levels.

Other options, such as aesthetic preference or requiring a uniform power supply for all fixtures, do not address the fundamental safety and operational concerns specified in the NEC. An oversized power supply may provide a buffer against overload, but it does not align with best practices for efficiency or safety as mandated by the code. Thus, ensuring the power supply is adequately rated is crucial for safe and effective lighting installation.