In my area, community colleges have trades programs for such things. I've gotten overrides for pre-reqs when I've audited classes for hobby rather than for the certificate/degree, allowing me to take the few core courses that cover most of what I'll get into in my projects.

Also, when applying for a home-owner permit, my city requires you pass a short test showing you know the basics of the code (not nearly as in-depth as certification exams).