Cal. Bus. & Prof. Code § 6740

A subordinate to a civil, electrical or mechanical engineer licensed under this chapter, or a subordinate to a civil, electrical or mechanical engineer exempted from licensure under this chapter, insofar as he or she acts solely in that capacity, is exempt from licensure under the provisions of this chapter. This exemption, however, does not permit any such subordinate to practice civil, electrical or mechanical engineering in his or her own right or to use the titles listed in Sections 6732, 6736, and 6736.1.