WAC 296-46B-235. Branch circuits, feeders, and services over 1,000 volts ac, 1,500 volts dc nominal

402(B) Wiring methods.

The installation of service entrance conductors exceeding 1,000 volts ac, 1,500 volts dc, nominal, within a building or structure must be limited to the following methods: Galvanized rigid metal conduit, galvanized intermediate metal conduit, schedule 80 polyvinyl chloride conduit, metal-clad cable that is exposed for its entire length, cablebus, or busways. Exception: Wiring methods per NEC 235.402(B) shall be permitted for service conductors within a building or structure when customer owned overcurrent protection in accordance with NEC requirements is provided outside the building.