almost everything you need to know is in the NEC, except for the business questions and a few about controls, transformer connections, etc. . .
the only thing you should watch out for is that most questions are simply trick questions. i breezed right through it and when looking it back over, i realized i missed a lot simply because i misread the question.
i took the NEC and an ugly's book. all of the tax questions already had the percentages listed in the question, so i didn't have to reference anything else. if you take every book on the reference list, be sure to watch your time; the poor guy next to me looked up every single question and told me he ran out of time on the first half; i was long gone before the second half ended so i'm not sure how he did there.
my test was mostly sizing feeders for welders, article 680, transformers, and i think i had several questions also on emergency systems. you'll have one or two questions on random subjects throughout the code. all the transformer questions were simply identifying the type of transformer, and then input and output voltages, all on 1:2 and 2:1 ratio's; extremely easy stuff.
its 8 hours divided in two 4 hour blocks. there's a 1 hour break between the two blocks. i spent an hour answering all the questions and 30min to an hour double-checking things i wasn't sure of.
lastly, there is a space on the back of the answer sheet for you to challenge questions that aren't correctly worded or don't give enough information. use it, because you will get points for it. if you have a question that doesn't have the 'correct' answer, just put the nearest answer and so forth. like i said, its mostly 'trick' questions; they just want to know that you can comprehend questions and can find answers in the code. that's it really.
good luck.
