NFPA 70: National Electrical Code (NEC) provides comprehensive requirements for electrical wiring and equipment and covers the installation of electrical conductors, equipment and raceways; signaling and communications conductors, equipment and raceways, and optical fiber cables and raceways for public and private premises; yards, lots, parking lots, carnivals and industrial substations; installations of conductors and equipment that connect to the supply of electricity; installations used by electric utilities, and recreational buildings, that are not an integral part of a generating plant, substation, or control center.
2014 National Electrical Code incorporates major changes that impact residential, commercial and industrial electrical installations including:
Four all-new articles expand NEC coverage (Article 393: Low Voltage Direct Current Distribution Systems; Article 646: Modular Data Centers; Article 728: Fire Resistive Cable Systems; Article 750: Energy Management Systems). Major changes in the 2014 NEC also respond to electrical safety concerns (new centralized locking requirements in revised section 110.25; revisions in section 110.21(B) dealing with field marking of equipment). The publication also improves the safety and efficiency of green energy systems (new direct current (DC) provisions are designed to save energy lost in conversion from AC; voltage thresholds are increased from 600 to 1,000 volts to be consistent with alternate energy technologies). Code changes are easily located through the use of shading for revised code text and vertical rules indicating new articles, tables and/or figures.