Class 1, 2, and 3 circuits are classified as remote-control, signaling, and power-limited circuits in the National Electrical Code (NEC). The NEC defines such circuits as that portion of the wiring ...

Class 2 circuits reclassified and installed as Class 1 circuits are no longer Class 2 circuits, regardless of their continued connection to a Class 2 power source [Sec. 725.130(A) Note]. Class 2 ...

Unlike Class 2 and Class 3 power-limited circuits, Class 4 circuits don’t limit power source output. Instead, they constantly monitor for faults and control the delivery of power current ...