The following Illinois government site contains information you might find useful.
Also, note that if you scroll down the page to the link titled "Illinois Municipal Code Directory" and click on it, you'll be taken to a page where you can enter your municipality and get the name and contact details of the responsible Code Official, as well as the prevailing Codes (click on your municipality name to open up a window with that information, although when I did so for Beardstown - unlike some other municipalities - there were no Code entries). You might want to have a chat with your Code Official before pursuing other options.
https://cdb.illinois.gov/business/codes/buildingcodesregulations.htmlAs you'll see when you read the summary text on the webpage, as of Jan. 2025 Illinois has adopted statewide building codes. However, which ones apply depend upon commercial or residential construction, and whether or not jurisdictions have already adopted building codes, etc. The only explicit mention of the National Electrical Code is its requirement in the section titled "Commercial buildings in jurisdictions that have not adopted a building code AND state funded buildings". Another reason to contact your Code Official.
