For connection to a ground rod, what is the minimum size grounding electrode wire needed for a 200-ampere residential service?

For a 200-ampere residential service, the choice of grounding electrode wire is critical for ensuring proper ground connection and safety. According to the National Electrical Code (NEC), the minimum size of grounding electrode conductor depends on the size of the largest service-entrance conductors feeding the service, and for a 200-amp service, a 6 AWG copper grounding electrode conductor is required.

This requirement exists to ensure that, in the event of a fault, the grounding system can carry the necessary fault current safely back to the source to trip the overcurrent protective devices. A 6 AWG copper conductor satisfies this need effectively, providing a balance between conductivity and physical durability, helping to protect against potential corrosion and mechanical damage when buried.

Choosing a grounding electrode conductor smaller than 6 AWG for this application could lead to inadequate performance during fault conditions, potentially jeopardizing safety and compliance with electrical codes. Larger conductors, such as 4 AWG or 2 AWG, may be more than necessary for this service size, which can increase material costs without providing additional benefit in this specific context.