Chicago is a union city. Chicago has large steel producing companies. It has always been this way. Chicago inspectors argue that emt is a better method than cable, both for grounding purposes as well as the ability to change wiring in the future without tearing open walls. Chicago claims to have a lower amount of electrical fires than other cities which allow all NEC methods. I don't think Chicago would allow flexible metal conduit, but I haven't delved into the new code yet. Also, Chicago does not allow more than nine wires in any conduit.
I am the inspector from Oak Park, IL, due west of central Chicago and we require emt for interior installations as well. Also, we require rigid for service conductors. But we follow the NEC otherwise. We use to follow Chicago code until 1984. Also we will allow AC, MC or flexible conduit to fish walls but NM cable is taboo here. If NM cable is ever discovered, the owner is notified that they have to get it removed. There are talks of going NEC no amendments, but there is also a strong opposition to it. I personally am opposed because I don't think Oak Park will ever supply enough help to properly regulate work going on without permits and the installations I see everyday would make any apprentice electrician cringe. Also, Oak Park is a completely developed community so the majority of work is remodeling and dealing with existing conditions. Oak Park still has a good percentage of homes with knob and tube wiring. For this reason, as well as I grew up in Chicago and that's just the way it's done, I prefer to see emt installations.
Welcome to the Windy City!!!
