When it comes to electrical safety, the National Electrical Code — or NEC — is the nationally recognized standard. The 1,000-page document is published every three years, and it’s up to states or local jurisdictions whether to adopt the code and how to enforce it.
Does Missouri Adopt and Enforce the National Electrical Code?
Generally speaking, states chose one of three options: 1) they adopt the NEC as state law and enforce the law statewide, 2) they only adopt and enforce the NEC at the local level, or 3) they opt for a hybrid situation in which the state adopts the NEC for certain situations, allowing local jurisdictions to adopt (or not) the code by their own will (source).
In Missouri, our state Department of Public Safety, Division of Fire Safety adopts the NEC and applies it to state-owned buildings. However, our local jurisdictions chose whether or not to adopt and enforce the code. (To find out if your community has adopted the NEC, contact your local city or county officials.)
Whether or not your local jurisdiction adopts and enforces the NEC, the code is still considered the preeminent standard and point of reference for electrical safety in the United States.
The History of the NEC
The NEC was first published in 1897. The National Fire Protection Association (NFPA) has developed and published the code since 1911, releasing an update every three years. The code is available in electronic and print versions, and the NFPA even publishes an NEC Handbook which includes the entire code, as well as helpful illustrations (source).
You can get free, restricted access to the NEC here if you’re willing to register with the NFPA.