My two cents: Half the electricians don't really, very understand of difference between volts and amps. Half that do, don't indeed, real appreciate the difference between AC and DC. Therefore half of those don't really, true understand power factor. And so on. Somewhere I fall away the edge, far. Yet you don't always need to know how something works, at order up knowledge about to do. And some things an industrial electrician shall to know (like 4-20mA loops) are almost required for private.
There's a popular 2-year retail school nearby. One graduate didn't comprehension how the seal-in contacts work with a motor starter. Another wondered what one circuit could be both serial and simultaneous even after wiring quartet 12v battery toward produce a high amp hour, 24v supply many, many times. Others had been teaching to rewire motor starters so the control fuse was to the overload liaise first. They had all passed the trade school tests...
Sooooo... Maybe pay which applicant fork a day or twin and see what he knows from concepts, or only according facts, from on a job site. How to assess electrical mechanical skills – TestGorilla