The ground wire that runs with your circuit (the equipment grounding conductor, or EGC) is primarily sized by your breaker rating, with some exceptions such as voltage-drop adjustments. A 20-amp breaker needs a #12 AWG copper EGC. A 200-amp feeder. The National Electrical Code (NEC) provides clear guidelines for ground wire sizing through Table 250. 122, but understanding how to apply these requirements correctly can make the difference between a safe installation and a costly code violation. The typical sizes of earthing conductors in Standard Wire Gauge (SWG) are as follows: Usage: This is often the minimum size recommended for general domestic applications. NEC Ground Wire Size Chart provides standard wire sizing for grounding conductors in electrical systems. It ensures safe fault current paths, compliance with NEC codes, and reliable protection for residential, commercial, and industrial installations. Grounding and Bonding and the NEC 250 Training. There are two distinct types of ground wire size charts as governed by the National Electric Code.
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