Which conductor is explicitly prohibited from being used to ground an appliance according to broader NEC guidelines?

The use of a white grounded circuit conductor as a grounding method for appliances is explicitly prohibited according to the National Electrical Code (NEC) guidelines. The white wire is designated as the neutral conductor, which is intended to carry current back to the source during normal operation. Using the white conductor for grounding compromises its primary function and could create a safety hazard.

In electrical systems, grounding serves to protect individuals from electric shock and to provide a path for fault currents to ensure that protective devices, like circuit breakers, operate correctly. The neutral should remain separate from grounding conductors to ensure that fault currents are effectively managed, and that the overall safety of the electrical system is maintained.

To ground an appliance properly, an uninsulated ground wire is the appropriate choice because it is specifically designed for that purpose. This ensures that any fault current has a clear, dedicated path to the ground, which allows protective devices to operate properly in the event of an electrical fault.