In which circumstance is a ground rod not required to be used?

A ground rod is not required when a concrete-encased electrode or other suitable grounding means is present because the primary purpose of grounding is to provide a safe path for fault currents and to establish a reference point for voltage levels. If an effective grounding method is already available, such as a concrete-encased electrode, which can provide a reliable connection to the earth, then the addition of a ground rod is not necessary.

Concrete-encased electrodes consist of reinforcing bars or metal mesh encased in concrete, which have a large surface area in contact with the ground and can effectively dissipate electrical energy, fulfilling grounding requirements. Therefore, in scenarios where concrete foundations are present and utilized as grounding electrodes, the code allows for flexibility regarding additional grounding methods like ground rods. This ensures safety and reliability in the electrical system without redundant installations.