The NEC makes a distinction between three types of ground conductors. Understanding their differences is important to designing, installing, and maintaining a safe system and avoiding some of the pitfalls that we'll discuss in future columns.
This conductor's job is to provide a low-impedance connection from earth to the neutral as a return path for current should a circuit supplied from the service inadvertently contact earth or a structure connected to earth. The conductor size is specified based on the size of the service entrance conductors and it is required to be installed continuously without splices unless they are of the irreversible compression or exothermic-welded type.