In this 2020 Code cycle a new Informational Note now accompanies the term Grounded Conductor where it is defined in Article 100. The Note has been added to help electricians identify functional differences between Grounded and Grounding Conductors.
In defense of all who have struggled with these terms in the past, both grounded conductors and grounding conductors are in fact grounded. They just have different jobs.
Prior to 2017, only two items were prohibited for use as grounding electrodes, underground gas piping and aluminum. For 2017, another item has been added to the list of prohibited items. For the 2017 NEC Code cycle, the structures as well as steel reinforcement materials that pertain to swimming pools have been added to the list found in 250.52(B)(3) of components that are prohibited from being used as grounding electrodes for an electrical system.
Why are you permitted to go no larger than #6 cu for the GEC attached to a driven rod or driven pipe that is being used as a grounding electrode, but you have to use Table 250.66, and all of the proposed size increases in it when using a metal water piping system in the earth, as my grounding electrode conductor?
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