Al;
From what I was just reading is;
Intent: The intent is to require all ungrounded (hot) circuit conductors terminating on multiple receptacles (duplex) on the same yoke to be disconnected simultaneously regardless of type of occupancy. This rule is intended to prevent persons from unintentionally working on energized circuits that they thought were disconnected. the 99 NEC only required the circuit disconnect to simultaneously interupt the multiwire circuit to multiple receptacles on the same yoke if the receptacle was located in a dwelling unit.
REF, MHE 2002 code changes.
