Wash. Rev. Code § 35.22.640
Cities of the first class are relieved from complying with the provisions of RCW 35.22.620 with respect to any public work or improvement relating solely to electrical distribution and generating systems on public rights-of-way or on municipally owned property: PROVIDED, That if a city-owned electrical utility directly assesses its customers a service installation charge for a temporary service, permanent service, or expanded service, the customer may, with the written approval of the city-owned electric utility, contract with a qualified electrical contractor licensed under chapter 19.28 RCW to install any material or equipment in lieu of having city utility personnel perform the installation. In the event the city-owned electric utility denies the customer's request to utilize a private electrical contractor for such installation work, it shall provide the customer with written reasons for such denial: PROVIDED FURTHER, That nothing herein shall prevent any first-class city from operating a solid waste department utilizing its own personnel.
If a customer elects to employ a private electrical contractor as provided in this section, the private electrical contractor shall be solely responsible for any damages resulting from the installation of any temporary service, permanent service, or expanded service and the city-owned electrical utility shall be immune from any tortious conduct actions as to that installation.
RCW 35.22.640