we ran #4 cu equip ground with 4/0 phase conductors in conduit with steel flex and ground bushing at xformer end; then paralled same for secondary to panel. We plan to run #3/0 system bonding ground (GEC) outside of pipe and tie GEC, equip grounds, xformer frame and XO together at transformer. Any input about whether this will create objectionable current? I thought we should have just run GEC in the conduit thru ground bushing and left out equipment ground but wire is already pulled.