California Code, Education Code - EDC § 17329

All drawings and specifications shall be prepared under the responsible charge of an architect, civil engineer, or structural engineer, who shall sign all drawings and specifications that are to be approved by the enforcement agency. Observation of the work of construction shall be under the general responsible charge, as defined by Section 6703 of Chapter 7 of Division 3 of the Business and Professions Code, of the architect, civil engineer, or structural engineer who signed the drawings, except that drawings and specifications not involving architectural or structural conditions may be prepared and the construction work may be administered by a registered professional engineer qualified in the branch of engineering that is appropriate to the drawings, specifications, estimates, and construction work.

If the architect, civil engineer, or structural engineer is unable to exercise general responsible charge of construction another architect, civil engineer, or structural engineer shall be retained to exercise general responsible charge of construction.