What is the minimum grounding conductor size for a residential building?

In a residential building, the minimum grounding conductor size is determined by the National Electrical Code (NEC) based on the size of the largest ungrounded conductor feeding the service. For residential services, if the largest ungrounded conductor is rated at 100 amperes or less, a 6 AWG copper grounding conductor or a larger gauge is typically required. The use of 6 AWG ensures that the grounding system can handle the fault current without overheating and provides sufficient protection for people and property.

Larger conductors provide better safety margins and ensure that the system complies with NEC regulations aimed at enhancing electrical safety in residential installations. The grounding conductor must be adequate to safely carry any fault current back to the ground to minimize shock hazards and equipment damage. Hence, selecting 6 AWG as the minimum grounding conductor size aligns with these safety and regulatory requirements.