What are the three circuit classifications typically covered under limited-energy cabling?

• A. Class 1, Class 2, and Class 3 circuits
• B. Class A, B, and C circuits
• C. Class X, Y, Z circuits
• D. Class 4, Class 5, Class 6 circuits

Answer: (A)

Limited-energy cabling uses energy-based categories to define safe wiring methods for low-voltage systems. The three classifications are Class 1, Class 2, and Class 3 circuits.

Class 2 circuits are the main power-limited category, designed so the energy level is very low to reduce shock and fire hazards. They’re commonly used for control, signaling, and information-transfer applications, which allows simpler installation rules and smaller protective requirements in many cases.

Class 3 circuits permit more energy than Class 2 but still stay within limits that keep hazards manageable. They’re used when more power or longer runs are needed, but the energy remains constrained to maintain safety.

Class 1 circuits cover the remaining scenarios that don’t meet Class 2 or Class 3 limits. They typically involve higher energy than Class 2/3 or different configurations, requiring more robust protection and installation considerations.

Understanding these three classifications helps determine appropriate cable construction, insulation, and routing so installations stay safe and code-compliant.