This was in a home built in 1991. The service panel was located on the exterior of the home with a 175 amp breaker. The interior distribution panel was located on the opposite side of the home in the basement. It was fed by a 3-wire feeder, not in a metallic raceway. So the EGCs and the grounded conductors were not isolated from each other and they connected the two together in the same lugs.
My question: Is it possible to correctly bond and ground a distribution panel with only a 3-wire feeder? Thanks.