Which of the following statements is true regarding luminaires that can be adjusted after installation?

The assertion that luminaires can have an exposed cord after installation is accurate within the context of the National Electrical Code (NEC). In certain applications, when luminaires are designed to be adjustable, the use of flexible cords is permissible as long as they comply with the necessary safety standards. For example, these luminaires may be employed in spaces where users need to frequently modify their position or angle, such as in track lighting.

It is crucial to consider that while an exposed cord can be acceptable, it is essential for such installations to adhere to safety requirements to prevent hazards, such as tripping or damage to the cord itself. All installations should prioritize safety and code compliance to ensure that the fixtures remain secure and function effectively without compromising safety.

In contrast, permanent plugs are typically not a requirement for luminaires designed to be adjustable, as these may rely on a different kind of installation that allows mobility. Secure mounting is also necessary across various luminaires, not just those that are adjustable, and the statement regarding exclusive use in residential settings is broad and misleading since adjustable luminaires can be utilized in commercial and industrial settings as well.