What is the minimum size copper grounding electrode conductor required for a detached garage fed from a dwelling with a 200 ampere breaker?

To determine the minimum size copper grounding electrode conductor required for a detached garage fed from a dwelling with a 200 ampere service, it's essential to refer to the National Electrical Code (NEC) which outlines the grounding and bonding requirements.

For a 200 amp service, the NEC specifies that the size of the grounding electrode conductor must be based on the size of the service entrance conductors. According to NEC Article 250.66, the minimum size of a grounding conductor for a building or structure depends on the size of the largest ungrounded conductor feeding the service.

For copper conductors, if the service is 200 amperes, the minimum requirement for the grounding electrode conductor is 4 AWG copper. This aligns with NEC guidelines, which provide clear standards to ensure safety and effectiveness in grounding systems. The 4 AWG size is significant because it offers sufficient conductivity to safely bond and ground the electrical system, preventing electrical shock hazards and ensuring equipment protection.

Specifically, using a larger conductor such as 2 AWG would exceed the minimum requirements, while smaller sizes like 6 AWG or 8 AWG do not meet the standard for a 200 amp service, making them inadequate for this application. Hence, a 4 AW