California Code, Public Utilities Code - PUC § 21659

(a) No person shall construct or alter any structure or permit any natural growth to grow at a height which exceeds the obstruction standards set forth in the regulations of the Federal Aviation Administration relating to objects affecting navigable airspace contained in Title 14 of the Code of Federal Regulations, Part 77, Subpart C, unless the Federal Aviation Administration has determined that the construction, alteration, or growth does not constitute a hazard to air navigation or would not create an unsafe condition for air navigation.

(b) Subdivision (a) does not apply to a pole, pole line, distribution or transmission tower, or tower line or substation of a public utility, as specified in Section 21658.