A new section was added to prohibit the use of the equipment grounding conductor as a grounding electrode conductor.

250.121 Use of Equipment Grounding Conductors. An equipment grounding conductor isn’t permitted to be used as a grounding electrode conductor.

Analysis: The grounding electrode conductor (GEC) is intended to help direct lightning-induced energy to the earth, while an equipment grounding conductor (EGC) is intended to provide a low-impedance ground-fault current path to the source to operate overcurrent devices in the event of a ground fault. The requirements for sizing are also different. An EGC is sized in accordance with 250.122, while a GEC is sized using 250.66. Because these conductors have different rules, different sizing requirements, and different installation requirements, this section was added to clarify that one conductor can’t fill the roles of both an EGC and a GEC.