Which is a feature of General-purpose single Type THHN conductors?

General-purpose single Type THHN conductors are designed for versatility in electrical installations, which makes them suitable for usage in conduit or cable tray. This is a key feature because these conductors are typically used in various wiring systems, where they can be easily installed in conduits—protecting them from physical damage and environmental conditions—or laid in cable trays for organized routing of electrical wiring.

These conductors are rated for dry and damp locations and can handle a range of applications, but their ability to be used in conduit or cable trays significantly enhances their functionality in both residential and commercial settings.

Other features listed, such as being designed for high currents or insulated against high temperatures, do not specifically define their general-purpose application. While THHN conductors do have high current-carrying capacities and are insulated to handle certain thermal limits, the primary and distinguishing aspect within the context of the question focuses on their adaptability for installation in various types of physical support systems, namely conduits and cable trays.