What is the primary purpose of bushings on outlet boxes?

The primary purpose of bushings on outlet boxes is to prevent wear on cords. Bushings provide a protective barrier where electrical cords pass through or come in contact with sharp edges of the box. This helps to safeguard the insulation on the cords from abrasion and potential damage, which could lead to short circuits or electrical failures. By mitigating wear and tear, bushings play a critical role in maintaining the integrity and safety of electrical installations, ensuring that cords remain functional and reducing the risk of electrical hazards.

Other options may be relevant in different contexts, but they do not capture the essential function of bushings in outlet boxes. Shock protection and enhanced conductivity are important aspects of electrical safety and performance, but bushings are specifically designed to address the issue of wear. Aesthetics, while a consideration in some design elements of electrical installations, are not a primary function of bushings.