California Code, Public Utilities Code - PUC § 12102

(a) When no list of eligibles is available for a position in the class requisitioned by the department or division head, the general manager may make a noncivil service appointment thereto for a period of not exceeding six months and only until a regular appointment can be made, but no person shall be compensated under a noncivil service appointment, or appointments, for a period exceeding six months in any fiscal or calendar year, and no office or employment may be filled by a noncivil service appointment for more than six months in the aggregate in one fiscal or calendar year.

(b) This section does not apply to a district which has owned or operated an electric distribution system for at least eight years and has a population of 250,000 or more.