The size of wire-type equipment grounding conductors is approximately what fraction of the circuit conductor size as per NEC Table 250.122?

According to the National Electrical Code (NEC) Table 250.122, the size of wire-type equipment grounding conductors (EGCs) is indeed specified relative to the size of the circuit conductors. For branch circuits rated at 15 to 200 amperes, the minimum size of the EGC is typically around 25% of the circuit conductor size. This relationship is critical for ensuring that the grounding conductor is adequately sized to carry potential fault currents safely without exceeding its temperature rating and without presenting a risk of fire or shock hazards.

By establishing a standard size for grounding conductors in relation to circuit conductors, the NEC helps ensure the safety and reliability of electrical systems, enabling adequate fault current paths. Adhering to this guideline helps prevent potential equipment damage and enhances the overall safety of electrical installations.