For a concrete-encased electrode, what is the minimum length of rebar, rods, or copper conductor required?

In the context of grounding and bonding, a concrete-encased electrode typically refers to a grounding system that consists of rebar, rods, or conductors embedded in concrete. The National Electrical Code (NEC) establishes specific requirements for the minimum length of these electrodes to ensure effective grounding.

The minimum length stipulated is 20 feet for rebar or copper conductors that are encased in concrete. This length is crucial because it helps establish a robust electrical connection to the earth, enhancing the grounding system's effectiveness. The longer the electrode, the greater the surface area in contact with the ground, which can decrease the resistance of the grounding system and improve safety by allowing any fault current to be effectively dissipated.

In contrast, options that propose lengths of 10, 15, or 25 feet do not align with the NEC requirements specifically established for concrete-encased electrodes. The specification of 20 feet is a standard that ensures a consistent level of grounding effectiveness across installations.