Which electrical component must be accessible when servicing a luminaire?

The requirement for accessibility in servicing a luminaire primarily pertains to the supply wiring. This is because the supply wiring connects the luminaire to the electrical system and is necessary for the luminaire to operate. When servicing or repairing a luminaire, it is critical to be able to access the supply wiring to safely disconnect power and ensure that any maintenance work can be completed without risk of electrical shock or damage.

In addition, accessibility to the supply wiring allows technicians to check for secure connections, inspect for wear, and troubleshoot any issues related to the power supply. Proper maintenance of the supply wiring helps in preventing faults that could lead to circuit failure or safety hazards.

The control panel is not always directly accessible when dealing with a single luminaire, as it may control multiple fixtures and is generally located away from individual units. The fixture housing is typically not something that needs to be accessed for servicing, unless there’s a need to replace the entire luminaire or access internal components. The ballast, while important to the operation of some types of luminaires, typically does not require accessibility during general servicing unless there's a specific issue with the ballast itself. In summary, ensuring access to the supply wiring is essential for safe and effective servicing of luminaires.