Here's a description of California's engineering licencing system. I found it on the NSPE website in a blog entry about pending legislation that would change all "title acts" to "practice acts."
"California has a unique engineering licensure system. There are three “practice act” disciplines: civil, mechanical, and electrical. These disciplines are authorized to practice engineering, and their practice is regulated by the California Board for Professional Engineers, Land Surveyors, and Geologists. Civil, mechanical, and electrical engineers can be held accountable for their professional misconduct, and their authority to practice can be suspended or revoked. There are also nine “title act” disciplines: agricultural, chemical, control systems, fire protection, industrial, metallurgical, nuclear, petroleum, and traffic engineering. In these disciplines, the state regulates the use of the title, but not the practice. In the case of misconduct, the board can revoke continued use of the title but cannot preclude continued practice. Title act engineers who commit professional misconduct can continue practicing as long as they do not continue using the title. Many state and local agencies refuse to accept documents stamped by engineers in these disciplines even though their reports are within their field of study and experience. Many fire protection and nuclear engineers, for example, are also licensed as mechanical engineers, but many of the title act engineers are not also licensed in either civil, mechanical, or electrical engineering. To make matters even more complicated, there are two “title authority acts,” for structural and geotechnical engineers, indicating proficiency in those specialties at a higher level than is required for civil engineering licensure."
I erred above when I said that "Civil", "Mechanical", and "Electrical" are protected titles. I meant to say protected practices. For a practice act engineer, both the practice and title are protected. For a title act engineer, only the title is protected. Of course, we still have industrial and governmental exemptions.
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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill