What type of equipment is covered in Article 630?

Article 630 of the National Electrical Code (NEC) specifically addresses the requirements for electric welders. This includes criteria related to installation, wiring methods, and safety measures that must be observed to ensure safe and effective operation of electric welding equipment. Electric welders are used in various applications for joining materials and require careful consideration of electrical safety practices due to the high currents involved during operation. Understanding the special provisions for these devices is essential for compliance with electrical safety codes and for protecting both the equipment and the users.

The other options do not fall under Article 630 because they pertain to different types of electrical equipment that are covered under separate articles in the NEC. For instance, X-ray equipment is addressed in Article 517, which focuses on health care facilities, while pipe organs would be covered in a different category focused on musical instruments and public address systems. Audio signal processing systems are also classified under different regulations that do not include the specifications laid out in Article 630. Therefore, the choice of electric welders aligns with the specific intent and scope of Article 630 within the NEC framework.