Chicago Code changed a few years ago into 1999NEC with some changes...and they're doozies. For example, NEC700 has been changed into something almost unrecognizable. Fortunately their Code books are organized and numbered just like NEC, so finding things is a lot easier. I usually figure in what NEC requires, then whip out my Chicago book to see if I need to change my approach. It's at least a couple of zillion times better that the OLD Chicago Code, that was basically a minimally updated 1957 code. Chicago even insisted that THEY approve products; not trusting UL with the safety of their fair city...and or course charging for those reviews. If you're considering an approach that would save time or people, you may find something in Chicago Code against it. This is still a "keep everybody busy" town.
The Chicago Code book is Layouted similar to the N.E.C. Except the Front section is all Chicago Rules and Regulations. Theres a LOT of Differences in the Rules between the too. To me the Chicago Code is Stricter and Better then the N.E.C. If working under it I;d say you;d better invest and get one! I took the test under the old format and believe me it was a nitemare compair to the current layout!!
Is the book really $200? Last time I bought one (1990), you could buy it in two forms. One just contained the electrical sections, while the "big" book also had the fire, building, and housing codes in it.
Personally, I like the Chicago code. Somehow they feel no need to re-write it every three years!
It's still available as 2 books so you don't have to lug the Steam Boiler Codes and stuff along everywhere. I bought mine (Electrical only) for the publisher from Index Publishing last year. They're at www.chicagocodes.com if you want to get a current price.