Which NEC article governs limited-energy Class 2 and Class 3 circuits?

• A. NEC Article 310
• B. NEC Article 725
• C. NEC Article 240
• D. NEC Article 720

Answer: (B)

Limited-energy Class 2 and Class 3 circuits are addressed by a single NEC article that sets the rules for how those circuits are defined, constructed, protected, and installed. That article defines what qualifies as Class 2 or Class 3 and provides the specific requirements for insulation, wiring methods, and protection, reflecting the lower energy levels and reduced hazards of these circuits. This makes it the exact reference point for any work involving limited-energy Class 2/3 circuits, ensuring consistent safety practices.

The other articles cover different parts of electrical installations: for example, one focuses on conductors and their ampacity, another on overcurrent protection, and the remaining one relates to a different category of circuits and equipment. Because they do not specifically govern limited-energy Class 2/3 circuits, they aren’t the correct reference for these circuits.