Which type of equipment is described in Article 660?

Article 660 of the National Electrical Code (NEC) specifically addresses the installation and safety requirements for X-ray equipment. This includes provisions for the wiring, grounding, and protection of electrical circuits that supply power to X-ray machines, which are used in medical imaging and industrial applications.

The article covers various aspects of X-ray equipment, ensuring that it operates safely and effectively while minimizing exposure to potentially harmful radiation. This makes the requirements unique to X-ray equipment compared to the other types of equipment listed in the options, which pertain to different applications and thus fall under different articles in the NEC. Induction heating equipment, swimming pools, and large-scale photovoltaic systems have their respective articles that delineate their specific electrical safety guidelines and installation requirements.