The NEC (National Electrical Code) is used in most parts of the United
States. The tamper resistant requirement is detailed in article 406.12.
Some parts of the country use the IRC (International Residential Code)
instead. However, it has a similar requirement for tamper resistant outlets
in section 4002.14.
I do not know which code is used in Chicago, and local jurisdictions may
have their own requirements (often stricter). The only way to know for sure
would be to contact your local permit agency to find out what they use.
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