Not to be confused with the grounded conductor, a grounding conductor is used to connect the frame or enclosure of an electrical device to earth ground. The grounding conductor is sometimes bare copper, but is more often covered with green insulation. Rarely seen but just as permissible is striped yellow and green insulation. Very occasionally a system uses orange insulation on the grounding conductor, but in this case signs must be posted noting that fact to prevent accidents.
On a standard 110 Volt grounded, polarized U.S. electrical plug, the grounding conductor is connected to the round prong set between and beneath the flat prongs. The thin flat prong is connected to the hot conductor and the wide flat prong is connected to the grounded, or neutral conductor.
The grounding conductor should never have current running through it, and should always be at zero Volts with respect to earth ground. These principles are important to the operation of the GFCI outlet.