320-Amp Service, Two 200-Amp Panels: GEC Sized on 4/0 or 320-Amp Rating?
Dual 4/0 SER feeders to separate 200A panels from a 320A pedestal — Table 250.66 says size GEC on largest ungrounded conductor, not parallel. Inspector wants 320A service basis. NEC text, table values, and field consensus for #4 vs #2 copper GEC.