Here is a link to their code book:
http://www.chicagoplumbingcode.com/...ser_op=view_page&PAGE_id=7&MMN_position=22:22
Chicago Electrical Code Book 2006
Item #: 120-8731-05
Author: Index Publishing
Publisher: Index Publishing
Format: Paperback
Your Price: $194.95
The Chicago Electrical Code, published annually, includes general electrical regulations, all basic ordinances governing administration of the code itself, rules involving general applications, installations involving special occupancies, special equipment or special conditions, construction specifications, tables and penalties.
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Maybe with some searching you might find it a bit cheaper? You might need the fire safety code book also for $115.
By the time you buy the books and pay for a test you spent about $400. If your lucky enough to take the test and pass I believe it will cost you more for the license fee, maybe $100 for a few years.
But your not done yet. That gets your license. To do your own work for a customer you need to register your business with Chicago (or most any other city/village), for a fee. They will want proof of insurance and maybe a bond. I imagie by that point you need a business status (DBA, Corp, etc.).
You have to register with every city/village you work in seperatly. The contractor registration fee should not cost more than $50 under IL law(should is they key word). Also once you pay the fee you should not have to pay that fee again the same year under IL law (I said should again). About half the places require a seperate bond to work there for a cost of $50-$100.
In another words passing an electrical test in IL is only about 1/3 of what's required to do customer pay jobs in most places.
I would sugest working for someone elce for a bit at least until you get a feel for the area and what's required. Such as many places in Northern IL require EMT inside and RMC for services and outside. The city has things like only "Chicago Approved" this, plenum rated everything, only iron back straps outside, etc.