Is there any possibility that 250.122(F)(2) was used to size the equipment ground? If the ground fault current is limited to less than 800A, then 1/0 equipment grounds are acceptable.
In addition, I wonder if individual OCPD on the parallel conductors would meet the requirements of 250.122(F)(1), for example if 'limiting lugs' were used so that the current on an individual phase conductor in an individual raceway was limited to less than 800A, would the 1/0 equipment ground be acceptable?
-Jon
