To calculate an appropriate ground conductor size, enter the information below. This is in accordance with Table 250. 122 of the NEC, which is the National Electrical Code. Others are. . Understanding and utilizing the NEC ground wire size chart helps professionals comply with National Electrical Code (NEC) standards, prevent costly errors, and maintain the reliability of ac systems in electrical installations in residential, commercial, and industrial environments. 122, but understanding how to apply these requirements correctly can make the difference between a safe installation and a costly code violation. So let's get started with What Size. . It requires a 6 AWG copper ground wire. THE FENCE SHALL BE GROUNDED SEPARATELY FROM THE GRID UNLESS OTHERWISE NOTED ON THE A PROPRIATE PROJECT DRAWING. SEE APPLICATION "S",THIS DRAWING, FOR REQUIREMENTS FOR HIGH VOLTAGE TOWERS AND PO ES D BY GROUNDING ANALYSIS.