i have just read in an electrical reference book that states a 400 amp exterior service panel must have two ground rods spaced six feet apart. i have searched and searched in the NEC but cannot find that info anywhere. is this true and if so where in the codebook? the closest thing i can find is article 250.24 (3) and it is referencing dual feed services. it says one will do. this service will have one line side feed pair of 350 mcm or maybe 500. can't remember for sure what power company said, but it will not be two sets of parallel lines coming in. one or two ground rods guys?