NECA offers a variety of ANSI-approved performance and workmanship industry … Contact online >>
NECA offers a variety of ANSI-approved performance and workmanship industry
NECA''s Codes and Standards Standing Committee is extensively involved with
ANSI C2 （、）、。 （Institute of Electrical and Electronics Engineers） 。"""NESC" IEEE 。
The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association.[1] Despite the use of the term "national," it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices.[2] In some cases, the NEC is amended, altered and may even be rejected in lieu of regional regulations as voted on by local governing bodies.
The "authority having jurisdiction" inspects for compliance with the standards.[3][4]
The NEC should not be confused with the National Electrical Safety Code (NESC), published by the Institute of Electrical and Electronics Engineers (IEEE). The NESC is used for electric power and communication utility systems including overhead lines, underground lines, and power substations.
The NEC is developed by NFPA''s Committee on the National Electrical Code, which consists of twenty code-making panels and a technical correlating committee. Work on the NEC is sponsored by the National Fire Protection Association. The NEC is approved as an American national standard by the American National Standards Institute (ANSI). It is formally identified as ANSI/NFPA 70.
First published in 1897, the NEC is updated and published every three years, with the 2023 edition being the most current. Most states adopt the most recent edition within a few of years of its publication. As with any "uniform" code, jurisdictions may regularly omit or modify some sections, or add their own requirements (sometimes based upon earlier versions of the NEC, or locally accepted practices). However, no court has faulted anyone for using the latest version of the NEC, even when the local code was not updated.[5]
The Deactivation and Decommissioning (D&D) customized extension of the electrical code standard defined by National Electrical Code was developed since current engineering standards and code requirements do not adequately address the unique situations arising during D&D activities at U.S. Department of Energy (DOE) facilities. The additional guidance is needed to clarify the current electrical code for these situations. The guidance document provides guidance on how to interpret selected articles of NFPA 70, "National Electrical Code" (NEC), in particular certain articles within Article 590, "Temporary Power," for D&D electrical activities at DOE sites.[7]
The NEC also contains information about the official definition of HAZLOC and the related standards given by the Occupational Safety and Health Administration and dealing with hazardous locations such as explosive atmospheres.
The NEC is available as a bound book containing approximately 1000 pages. It has been available in electronic form since the 1993 edition. Although the code is updated every three years, some jurisdictions do not immediately adopt the new edition.
The NEC is also available as a restricted, digitized coding model that can be read online free of charge on certain computing platforms that support the restricted viewer software; however this digital version cannot be saved, copied, or printed.
The introduction and the first 8 chapters contain numbered parts, articles, sections (or lists or tables), item, specifics, inclusions/exclusions, precise inclusion/exclusion, italicized exceptions, and explanatory material – explanations that are not part of the rules. Articles are coded with numerals and letters, as ###.###(A)(#)(a). For example, 805.133(A)(1)(a)(1), would be read as "article 805, section 133, item (A) Separation from Other Conductors, specific (1) In Raceways, cable Trays, Boxes,... inclusion (a) Other Circuits, precise inclusion (1) Class 2 and Class 3...." and would be found in Chapter 8, Part IV Installation Methods Within Buildings. For internal references, some lengthy articles are further broken into "parts" with Roman-numerals (parts I, II, III, etc.).
Each code article is numbered based on the chapter it is in. Those wiring methods acceptable by the NEC are found in chapter 3, thus all approved wiring method code articles are in the 300s. Efforts have been underway for some time to make the code easier to use. Some of those efforts include using the same extension for both code articles and for the support of wiring methods.
The NFPA also publishes a 1,497-page NEC Handbook (for each new NEC edition) that contains the entire code, plus additional illustrations and explanations, and helpful cross-references within the code and to earlier versions of the code. The explanations are only for reference and are not enforceable.
Article 210 addresses "branch circuits" (as opposed to service or feeder circuits) and receptacles and fixtures on branch circuits.Electrical Construction and Maintenance Magazine, Branch Circuits, Part 2. There are requirements for the minimum number of branches, and placement of receptacles, according to the location and purpose of the receptacle outlet. Ten important items in Article 210 have been summarized in a codebook.[10]
A ground fault circuit interrupter (GFCI) is required for all receptacles in wet locations defined in the Code. The NEC also has rules about how many circuits and receptacles should be placed in a given residential dwelling, and how far apart they can be in a given type of room, based upon the typical cord length of small appliances.
As of 1962, the NEC required that new 120 Volt household receptacle outlets, for general purpose use, be both grounded and polarized. NEMA connectors implement these requirements.
The NEC also permits grounding-type receptacles in non-grounded wiring protected by a GFCI; this only applies when old non-grounded receptacles are replaced with grounded receptacles, and the new receptacles must be marked with ''No equipment ground'' and ''GFCI Protected'' .
The 1999 Code required that new 120/240 volt receptacles, such as those for electric ranges and dryers, be grounded also, which necessitates a fourth slot in their faces. Changes in standards often create problems for new work in old buildings.
Unlike circuit breakers and fuses, which only open the circuit when the current exceeds a fixed value for a fixed time, a GFCI device will interrupt electrical service when more than 4 to 6 milliamperes of current in either conductor leaks to ground. A GFCI detects an imbalance between the current in the "hot" side and the current in the "neutral" side. One GFCI receptacle can serve as protection for several downstream conventional receptacles. GFCI devices come in many configurations including circuit-breakers, portable devices and receptacles.
Another safety device introduced with the 1999 code is the arc-fault circuit interrupter (AFCI). This device detects arcs from hot to neutral that can develop when insulation between wires becomes frayed or damaged. While arcs from hot to neutral would not trip a GFCI device since current is still balanced, circuitry in an AFCI device detects those arcs and will shut down a circuit. AFCI devices generally replace the circuit breaker in the circuit. As of the 1999 National Electrical Code, AFCI protection is required in new construction on all 15- and 20-amp, 125-volt circuits to bedrooms.[11]
The NEC requires that conductors of a circuit must be inside a raceway, cable, trench, cord, or cable tray. Additional protection such as NM cable inside raceway is needed if the installation method is subjected to physical damage as determined by the authority having jurisdiction.
The temperature rating of a wire or cable is generally the maximum safe ambient temperature that the wire can carry full-load power without the cable insulation melting, oxidizing, or self-igniting. A full-load wire does heat up slightly due to the metallic resistance of the wire, but this wire heating is factored into the cable''s temperature rating. (NEC 310.10)[12]
The NEC specifies acceptable numbers of conductors in crowded areas such as inside conduit, referred to as the fill rating. If the accepted fill rating is exceeded, then all the cables in the conduit are derated, lowering their acceptable maximum ambient operating temperature. Derating is necessary because multiple conductors carrying full-load power generate heat that may exceed the normal insulation temperature rating. (NEC 310.16)
The NEC also specifies adjustments of the ampacity for wires in circular raceways exposed to sunlight on rooftops, due to the heating effects of solar radiation. Electrical Construction and Maintenance Magazine, Conductors for General Use, Chapter 3 Articles in NEC, starting with Article 342 This section is expected to be modified to include cables in future editions.
In certain situations, temperature rating can be higher than normal, such as for knob-and-tube wiring where two or more load-carrying wires are never likely to be in close proximity. A knob-and-tube installation uses wires suspended in air. This gives them a greater heat dissipation rating than standard three-wire NM-2 cable, which includes two tightly bundled load and return wires.[13]
IEC is actively engaged in developing codes and standards for the electrical industry. Through the national Codes and Standards Committee, IEC is directly involved in a large variety of codes and standards activities including representation on 18-code making panels of the National Fire Protection Association’s (NFPA) 70 National Electrical Code (NEC), NFPA 70 E Standard for Electrical Safety in the Workplace, NFPÅ 820 Standard for Fire Protection in Wastewater Treatment and Collection Facilities, and NFPA 73 Standard for Electrical Inspections for Existing Dwellings.
The IEC Codes and Standards Committee collaborates with all of the electrical industry associations to develop the NEC. IEC also participates in the development of the National Electrical Safety Code and reviews standards created by Underwriters Laboratories, Inc. (UL).
IEC participation directly impacts the electrical industry.
About National electrical codes and standards
As the photovoltaic (PV) industry continues to evolve, advancements in National electrical codes and standards have become critical to optimizing the utilization of renewable energy sources. From innovative battery technologies to intelligent energy management systems, these solutions are transforming the way we store and distribute solar-generated electricity.
When you're looking for the latest and most efficient National electrical codes and standards for your PV project, our website offers a comprehensive selection of cutting-edge products designed to meet your specific requirements. Whether you're a renewable energy developer, utility company, or commercial enterprise looking to reduce your carbon footprint, we have the solutions to help you harness the full potential of solar energy.
By interacting with our online customer service, you'll gain a deep understanding of the various National electrical codes and standards featured in our extensive catalog, such as high-efficiency storage batteries and intelligent energy management systems, and how they work together to provide a stable and reliable power supply for your PV projects.
