Re: inspector
I was employed in NC as an electrical inspector level 2, and building inspector level 1, plumbing inspector level 1, and mechanical inspector level 1. I was state licensed as an electrical contractor (limited). I had very minimal experience in the other three areas. The primary reason being "certified" in the other trades, was to inspect house trailer installations. All four certs applied. The skill level was, as I say, minimal, but that was my only area of inspections.
Now that I'm in WI, the inspectors here are Master Electricians, with two levels of electrical inspector credentials. Journeymen, Masters, & inspectors are required to take between 12-18 hours of training in a three year period (length credential is valid). The inspectors that check our work have been field electricans sometime during their careers.