Which table specifies how luminaires and equipment must be sized in accordance with an equipment grounding conductor?

Table 250.122 is the correct reference for sizing equipment grounding conductors. This table outlines the minimum size requirements for grounding conductors that are used to ensure safety in electrical systems, particularly in regard to equipment like luminaires and other devices.

The purpose of an equipment grounding conductor is to provide a low-resistance path for fault current, which helps to prevent electrical shock hazards and allows overcurrent protective devices to operate properly in the event of a fault. The sizes specified in this table are directly related to the ratings of the overcurrent protective devices and the type of equipment or luminaires being used.

This reinforces the importance of selecting the proper size for grounding conductors in accordance with the electrical installation, ensuring that they are capable of safely carrying fault currents without posing a risk of fire or injury. The other tables mentioned do not relate specifically to the sizing of grounding conductors for luminaires and equipment, which is why this choice is the most fitting for the question asked.