NFPA 70: National Electrical Code
Standard for electrical installations
Last update 09/06/2021
NFPA 70 or NATIONAL ELECTRICAL CODE is the reference standard for electrical installations in premises and buildings in USA.
The ﬁrst National Electrical Code was developed in 1897. In 1911, the National Fire Protection Association (NFPA) became the sponsor, and the Code has been revised on numerous occasions since that date. Now it is revised every three years. The latest edition is 2020. The NEC is available for adoption as the electrical law in a governmental jurisdiction. That governmental jurisdiction may add one or more amendments to allow for local needs, preferences, or conditions (see for example the Chicago Electrical Code).
The code was born soon after Thomas A. Edison's Pearl Street Station was installed in New York City in 1882. Electrical fires were becoming commonplace and, by 1897, the problem was reaching epidemic proportions. A diverse group of knowledgeable, concerned individuals assembled to address this critical issue. The need for standardization was apparent. The consensus of more than 1200 individuals produced the first set of nationally adopted rules to govern electrical installations and operations: the National Electrical
Code was born. The NEC states its purpose as "the practical safeguarding of persons and property from hazards arising from the use of electricity". This objective has remained constant throughout the NEC’s existence, and the principles it contains continue to grow and change with the dynamic electrical industry.
The NFPA 70 or NEC is the reference standard for several electrical standards among which: