What is one of the installation requirements for Type UF-B conductors?

Type UF-B conductors are specifically designed for both indoor and outdoor applications, making them suitable for a variety of installations. The ability to be used in wet locations distinguishes Type UF-B conductors from other types that may be limited to dry areas. This versatility allows for their use in below-grade installations or where exposure to moisture may occur, such as in outdoor settings or in areas prone to dampness, which are commonly encountered in residential and commercial settings.

The other options do not align with the characteristics of Type UF-B conductors. For example, the claim that Type UF-B conductors are rated for interior use only contradicts their specification for outdoor use as well. Similarly, while conduit may be necessary for some installations, Type UF-B conductors do not require it in every situation, especially when installed in places where they can be protected by suitable coverings. Finally, restricting their use to above-ground applications overlooks their adaptability and usability in a range of environmental conditions, including subterranean applications.