What type of conductors can Class 2 and 3 circuits not be placed together with?

Class 2 and Class 3 circuits have specific requirements concerning their placement with other types of conductors. The key to understanding why power conductors cannot be placed with Class 2 and Class 3 circuits lies in the nature of the voltages and the functions these circuits serve.

Class 2 and Class 3 circuits are typically low-energy circuits, meant for signaling, control, and communications applications. They are designed to limit the amount of energy they can deliver, which reduces the risk of electric shock and fire hazards. In contrast, power conductors carry higher voltages and larger amounts of current, which can pose significant risks if not properly managed.

When Class 2 and Class 3 circuits are run alongside power conductors, there is a potential for interference and electromagnetic induction, which can lead to malfunctions of the low-voltage circuits. Additionally, the safety protocols established in the National Electrical Code (NEC) prohibit the mixing of these circuits in order to maintain safety and ensure that the lower voltage circuits remain isolated from the higher power circuits, which could otherwise cause accidental energization.

This regulation helps ensure that equipment operated at lower voltages—such as alarms, data transmission lines, and control signals—do not experience disruptions or cause harmful incidents