Is plastic conduit allowed as a grounding conductor in any application?

Plastic conduit is not permitted as a grounding conductor in any application, which is why the answer is that it is prohibited. The National Electrical Code (NEC) specifies that grounding conductors must be made of conductive materials to ensure they effectively provide a path for fault current. Plastic conduit is an insulating material and does not have the ability to conduct electricity, which is essential for grounding applications.

In grounding systems, the primary function is to safely direct fault currents to the ground, preventing electric shock hazards and equipment damage. Since plastic does not conduct electricity, it fails to meet the fundamental requirement for a grounding conductor. Therefore, any installations intending to provide a safe grounding path would need to utilize approved metallic conductors or other conductive methods outlined by electrical standards, rather than relying on plastic materials.