Which of the following statements is true about THHN conductors?

THHN conductors are primarily designed for dry locations and are not suitable for direct burial, as they do not have the moisture resistance required for such applications. They are often used in conduit or raceways, which provide additional protection against environmental factors.

On the other hand, options that suggest they are rated for use in places such as direct burial or underground applications are incorrect. Such installations require cables specifically rated for those conditions, typically found in types of conductors like UF (underground feeder) cable, which are designed to withstand exposure to moisture and other elements found in direct burial situations. Therefore, understanding the limitations of THHN conductors is crucial for ensuring compliance with electrical codes and safety standards in various installation environments.