installer, but at a certain point I realized that I reliably knew more about the code and electrical theory than many EC's I encountered working for the same clients. Last couple years I'm calling them out for their major mistakes (swapped neutrals, missing EGC to outbuilding, etc.) on a fairly regular basis. So now when people ask me if I'm an electrician I just shrug and say 'yeah'.
This is a bit where I am at. There are lots in that book I dont know, most of it is passing interest or in special circumstances I am part of. The parts I do use I know well, like you said,,, in comparison to some stuff we see,,, not sure how to word this/that but I am sure you get that. Service entrance, ruff a house, rewire, every screw and staple, the special circuits, etc and small shop especially welders, comps, requirements and allowances etc. Cords, cord sizing with hi degree of awareness as to sizing for fault protection and methods,,, etc. Not at engineer level but what they meant when they designed it and how they comply with code.
Welding machines are especially interesting in this area, have all the requirement and allowance and so many fundamental principles wrapped up in 2 conductors and a ground. Welders prove a point as to how the fundamental circuyit hasnt changed for 100 years and how they have changed the nachine over so many generations to comply with code.
There seems to be some feeling that poco and outfits like nema and ul do not have standards and they can simply make it up. Seems so many have not read the front of the books and I do not mean study but simply miss the parts that reference the nec and that they cannot pass it if it violates a code standard, size of a cord, max load on fixture wires and what thoise outfits do is certify it is legal to plug in to a proper legal circuit. This includes the fact that it must be designed proper when the tool is depending on the breaker for its own fault protection,,,,,,,,,,,,,,,,, this I cant believe they are not beat in school with till itsa understood and have seen lots of guys with paper do not grasp this concept. That there is another current limiting function of the breaker besides thermal like on a power strip.
Lots of masters on electric on other forums do not seem too involved in making this clear. In some defence when the answer is 6 wire on every 50A welder then most of that takes care of itself. What is disapointing is the cheering section some guy gets when he comes along and says,,, well I used number 8 and 80 so it will run all my welders,,, thats ok cause it wont overheat the wire in the wall.
Very few say,,,, wait a minute,,, the 200A mig not sposed to be plugged in to an 80 circuit?