A concrete-encased electrode requires how much bare copper not smaller than 4 AWG?

The requirement for a concrete-encased electrode involving bare copper not smaller than 4 AWG is specifically 20 feet, as stated in the National Electrical Code (NEC). This requirement ensures proper grounding and bonding for electrical systems. The use of 20 feet of this type of electrode helps to ensure that it has a sufficient length in contact with the soil to achieve the desired grounding effectiveness.

The concrete-encased electrode serves as a critical component to facilitate electrical grounding through its interaction with the surrounding concrete, which typically has a significant amount of moisture, enhancing conductivity. This length specification helps to ensure that electrical faults have a safe path to ground, thereby minimizing risk to equipment and personnel. The choice of bare copper is important due to copper's excellent conductivity and resistance to corrosion, which impacts the durability and longevity of the grounding system.

By ensuring that the grounding electrode is of the appropriate length and conductor size, it contributes to maintaining electrical safety and system reliability in compliant installations.