Which type of cable is not permitted for service entrance conductors?

Service entrance conductors must meet specific requirements to ensure safe and reliable operation within electrical systems. In this context, UF (Underground Feeder) cable is not permitted for use as service entrance conductors.

This is largely due to the construction and intended application of UF cable, which is primarily designed for underground use with a focus on protecting wiring from moisture and physical damage when buried. Its insulation and design characteristics make it less suitable for the exposure to weather and ambient conditions that service entrance conductors typically face when installed above ground, especially in visible and accessible locations such as the entry point of a building.

On the other hand, NM (Non-Metallic), MC (Metal-Clad), and TECK cables are better suited for service entrance applications. NM cable is used in dry locations and is economical for interior wiring, while MC cable features a metal sheath that provides enhanced protection and grounding capabilities. TECK cable is specifically designed for use in hazardous conditions and can handle higher ratings, making it appropriate for service applications.

Therefore, UF cable’s limitations and intended use define why it is not acceptable for service entrance applications, ensuring that safety and performance standards are upheld in electrical installations.