Which type of cable is identified for use as underground service-entrance cable?

Underground Service Entrance (USE) cable is specifically designed for installation underground and is rated for direct earth burial. This type of cable has a robust construction that provides protection against moisture and physical damage, making it ideal for service entrances that are installed underground. The insulation material and overall design of USE cable adhere to the necessary building codes and safety standards, ensuring that it can reliably conduct electricity in potentially harsh underground environments.

In contrast, other types of cable listed do not have the same suitability for underground installation. MC (metal-clad) cable, while versatile, is typically used for indoor or above-ground applications. NM (non-metallic) cable is intended for indoor use and cannot be exposed to moisture or direct burial. AC (armor-clad) cable has some protective features but is also primarily intended for above-ground installations. Thus, the use of USE cable is the correct choice when it comes to underground service-entrance applications because of its specifically developed characteristics for this type of environment.