What is a primary feature of the NEC definition of 'in sight' concerning electrical components?

The primary feature of the NEC definition of 'in sight' is that components must be visible without obstruction. This definition ensures that electrical components can be easily seen, which is crucial for both safety and maintenance purposes. Visibility without obstruction means that the components can be readily inspected and accessed by personnel, enabling them to perform necessary work without hindrance. This requirement helps to prevent accidents and makes troubleshooting more efficient.

Other options, while related to safety and accessibility considerations, do not capture the essence of the 'in sight' definition as clearly. Accessibility by authorized personnel and the specific locations of components—whether indoors or outdoors—are important, but they do not primarily address the visibility aspect that is at the heart of the 'in sight' definition in the NEC.