Rule 250.122 (B) says "Where ungrounded conductors are increased in size from the minimum size that has sufficient ampacity for the intended installation, wire-type equipment grounding conductors, where installed, shall be increased in size proportionately...". What defines "the minimum size"? For example, (using values for copper from 75° C column of T310.15 (B) (16) and assuming no factoring is required), 600 kcmil is frequently used. But parallel # 3/0 (167.8 kcmil) could also be used (obviously with paralleled EGCs). Using this option, is the minimum size to be considered 335.6 kcmil?