Which component serves as the primary ground-fault return path in a wiring device?

The component that serves as the primary ground-fault return path in a wiring device is the grounding wire. This wire is an essential safety feature in electrical systems, providing a low-resistance path for electric current to flow back to the ground in case of a fault. When there is a ground fault, the grounding wire helps ensure that any stray electricity is safely redirected, preventing electrical shock or fire hazards.

While the mounting strap, terminal block, and receptacle cover play roles in the overall structure and function of a wiring device, they do not serve as a grounding path. The mounting strap may support the device and provide structural integrity but does not function in grounding. The terminal block facilitates connections and provides a stable point for wires but is not involved in grounding faults. The receptacle cover protects the receptacle itself and individuals from contact with live parts but does not have a grounding role.