California Code, Government Code - GOV § 85307

(a) The provisions of this article regarding loans apply to extensions of credit, but do not apply to loans made to a candidate by a commercial lending institution in the lender's regular course of business on terms available to members of the general public for which the candidate is personally liable.

(b) A candidate shall not charge interest on any loan the candidate made to the candidate's campaign.  This subdivision does not apply to a jurisdiction in which the county or city imposes a limit on contributions pursuant to Section 85702.5.