What is the minimum size for Class 3 single conductors used as other wiring within buildings?

The minimum size for Class 3 single conductors used as other wiring within buildings is 18 AWG. This specification is established in the National Electrical Code (NEC), which outlines safety standards for electrical installations. Class 3 circuits are designed for low voltage distribution where the voltage is below 60 volts. The use of 18 AWG wire is considered adequate for the thermal performance and current-carrying capacity of these circuits, ensuring that they can function safely without the risk of overheating or other electrical hazards.

In residential and commercial wiring practices, utilizing wire gauge that is too small can lead to increased resistance and potential overheating, whereas the 18 AWG size strikes a balance between being sufficiently robust for its intended purpose while remaining manageable for installation. By adhering to this minimum wire size, electricians can ensure compliance with legal standards and promote the safety and reliability of electrical systems within buildings.