Sometimes called an “earth” or “earthing” wire, this is an intentionally grounded wire used to complete a circuit if the neutral conductor fails.
The PE ground wire is connected to the earth to create an electrical path of resistance, allowing electrical current to safely reach the ground.
In U.S. applications, the ground wire can be bare copper, or insulated with green, green/yellow, or black polyethylene (PE). PE offers excellent abrasion resistance and can be used in direct burial applications.