What is the minimum size of a grounding electrode conductor for a 100-amp service?

The minimum size of a grounding electrode conductor (GEC) for a 100-amp service is determined based on the material and the size of the service conductors as outlined in the National Electrical Code (NEC). For a service of this rating, the minimum requirement states that the grounding electrode conductor should be at least No. 8 AWG when made of copper or No. 6 AWG when composed of aluminum. This ensures adequate conductivity and safety in grounding systems.

Choosing No. 8 AWG copper aligns with the NEC requirements, as it provides sufficient current-carrying capacity to handle fault current and helps in effective grounding of the electrical system. Similarly, for aluminum, No. 6 AWG meets the necessary requirements.

In a grounding system, the size of the grounding electrode conductor is crucial for ensuring that it can effectively carry fault currents back to the ground system without overheating or failing, thereby providing protection against electrical shock and fire hazards.