What is true about the installed grounding systems according to the NEC?

The statement that grounding systems must be continuous to the ground aligns with the requirements established in the National Electrical Code (NEC). A continuous grounding system ensures that there are no breaks or discontinuities in the grounding path, which is crucial for safety. This continuity allows for a reliable return path for fault currents, which helps to prevent electrical shock hazards and equipment damage.

A grounded system that is not continuous could result in ineffective grounding, increasing the risk of electrical faults not being effectively cleared, thereby endangering both equipment and personal safety. Maintaining a continuous connection also supports the overall effectiveness of the grounding system in dissipating electrical energy safely into the earth.

While flexibility might be a desirable quality in certain applications, it is not a requirement of the NEC for grounding systems. Impedance is also not a relevant factor in the continuity aspect of grounding; rather, the focus is on creating a reliable, low-resistance path to ground. Furthermore, the choice of materials for grounding systems is specified by the NEC to ensure they meet certain conductivity and corrosion resistance standards, rather than being considered "any material." Therefore, the emphasis on a continuous grounding system is key to fulfilling NEC requirements and ensuring safety.