For AC premises wiring systems the identified conductor must be grounded.
Wash. Admin. Code § 296-307-36621
97-09-013, recodified as § 296-307-36621, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040,[49.17.]050 and [49.17.]060. 96-22-048, § 296-306A-36621, filed 10/31/96, effective 12/1/96.