The following electrodes are permitted for grounding.

Question

Quizplus · Accepted Answer

All three options are permitted for grounding, but the concrete encased electrode is often the best choice because it has a lower resistance to ground and is less likely to be affected by moisture or corrosion. However, if the building does not have a concrete-encased electrode, the metal frame of the building or interior metal water piping may also be used as long as they are within 5ft of the point where the grounding conductor enters the building.

The Following Electrodes Are Permitted for Grounding