When I renovated my old house I replaced all the wiring myself. It inspected without any issues. My new house (a tract house in a new sub-division) it was wired and inspected by professionals. When I plugged in the stove I discovered the outlet was not connected properly.

I hired out the replacement of my holding tank to a "professional". He hooked up the intake and pump out hoses backward. Good thing I checked that before using it. I find I can do a better job than most "professionals". Maybe certified electronics installers are different - but I doubt it.