Re: grounding conductor size
Grounding Electrode Conductors are sized based on the size of the service entrance conductor. Assuming this is a typical 200-amp installation ,2/0 copper would be used per Table 310.15(B)(6). Table 250.66 then shows a #4 copper being a large enough size. If your service entrance conductors are larger, see 250.66 for the correct size. If the GEC is going to be connected to a ground rod or pipe, #6 will be the largest you would have to go, #4 for concrete-encased electrodes, everything else use 250.66
