California Code, Public Utilities Code - PUC § 1701

(a) All hearings, investigations, and proceedings shall be governed by this part and by rules of practice and procedure adopted by the commission, and in the conduct thereof the technical rules of evidence need not be applied. No informality in any hearing, investigation, or proceeding or in the manner of taking testimony shall invalidate any order, decision, or rule made, approved, or confirmed by the commission.

(b) Notwithstanding Section 11425.10 of the Government Code, Articles 1 to 15, inclusive, of Chapter 4.5 (commencing with Section 11400) of Part 1 of Division 3 of Title 2 of the Government Codedo not apply to a hearing by the commission under this code.The Administrative Adjudication Code of Ethics (Article 16 (commencing with Section 11475) of Chapter 4.5 of Part 1 of Division 3 of Title 2 of the Government Code) shall apply to administrative law judges of the commission.