What does the term "exposed" refer to in terms of wiring methods?

The term "exposed" in the context of wiring methods refers specifically to wiring that is on or attached to the surface of walls, ceilings, or other structural elements. This means that the wiring is not concealed within walls, floors, or ceilings, making it visible and accessible. This visibility is significant in terms of safety and maintenance since exposed wiring is subject to physical damage and may require additional protection as per the NEC.

Other options relate to wiring methods that are either well-protected or concealed, which does not fit the definition of "exposed." For instance, wiring hidden under flooring or placed in insulated boxes is not visible to the eye and, therefore, wouldn’t be classified as exposed. Similarly, wiring in conduit, while it does offer protection and can be installed on surfaces, is encased in a protective covering that reduces its exposure to environmental factors. Thus, the correct choice clearly aligns with the definition and understanding of exposed wiring within the electrical code framework.