The National Electrical Code is sponsored by the National Fire Protection Association (NFPA). Not all states are up to date with the current electrical code. You can find out which version your area is using by calling your local Building Department and talking to the electrical inspector or building offical.

2014, 2017, & 2020 Code Books
The Code In Pictures
2008, 2011, 2014, 2017, and 2020 Ammunition Combo