Luminaires designed for end-to-end assembly can include a branch circuit supplying what type of setup?

Luminaires designed for end-to-end assembly often require configurations that support multiple luminaires connected together in a series or parallel arrangement. A multi-wire branch circuit is suitable for this setup because it allows several luminaires to be powered from a single circuit. This is beneficial for ensuring that the electrical load is evenly distributed and can provide the necessary power to multiple fixtures without needing separate circuits for each one.

Additionally, a multi-wire branch circuit can be advantageous for reducing the amount of wiring needed in a system while still maintaining the necessary voltage and current availability to multiple luminaires. This type of configuration is explicitly supported by the National Electrical Code, as it promotes efficiency and ease of installation in lighting systems.

In contrast, the other options do not fit the context of luminaires designed for assembly. A single luminaire may not fully utilize the capabilities of such a design, while multiple unconnected luminaires do not utilize the end-to-end assembly concept. Grounded connections alone do not define the electrical setup; they pertain more to safety and do not address the capability of powering multiple luminaires from a single circuit.