Each DISTRIBUTION BOX and controller must be grounded. Grounding of the units: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. It ensures safe fault current paths, compliance with NEC codes, and reliable protection for residential, commercial, and industrial installations. 26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. Copper wires, known for better conductivity, are generally preferred, but aluminum wires can also be used if upsized correctly. The EGC size chart is based on breaker size, not load, because the ground wire must be thick enough to withstand a short-circuit. This is the Grounding Electrode Conductor (GEC) size, determined by the size of your service entrance conductors (for example, 2/0 AWG copper or 4/0 AWG aluminum) as specified in NEC Table 250.
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