California Code, Probate Code - PROB § 4101

(a) Except as provided in subdivision (b), the principal may limit the application of any provision of this division by an express statement in the power of attorney or by providing an inconsistent rule in the power of attorney.

(b) A power of attorney may not limit either the application of a statute specifically providing that it is not subject to limitation in the power of attorney or a statute concerning any of the following: