Article 1. General of California Evidence Code >> Division 5. >> Chapter 1. >> Article 1.

Except as otherwise provided by law, a party has the burden of proof as to each fact the existence or nonexistence of which is essential to the claim for relief or defense that he is asserting.
Insofar as any statute, except Section 522, assigns the burden of proof in a criminal action, such statute is subject to Penal Code Section 1096.
The court on all proper occasions shall instruct the jury as to which party bears the burden of proof on each issue and as to whether that burden requires that a party raise a reasonable doubt concerning the existence or nonexistence of a fact or that he establish the existence or nonexistence of a fact by a preponderance of the evidence, by clear and convincing proof, or by proof beyond a reasonable doubt.