NFPA 70-2014 National Electrical Code (Effective Date 8 21 2013).pdf

1、NFPA70 National Electrical Code 2014 Edition NFPA, 1 Batterymarch Park, Quincy, MA 02169-7471 An International Codes and Standards Organization 7 /13Copyright 2013National Fire Protection AssociationOne Batterymarch Park Quincy, Massachusetts 02169-7471NFPA, NFPA 70, National Fire Protection Associa

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29、he Secretary, Standards Council, NFPA, 1 Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101; email: stds_adminnfpa.orgFor more information about NFPA, visit the NFPA website at www.nfpa.org.12/12Copyright 2013, National Fire Protection Association. All Rights ReservedNFPA 70National Electrical

30、Code2014 EditionThis edition of NFPA 70, National Electrical Code, was prepared by the National Electrical CodeCommittee and acted on by NFPA at its June Association Technical Meeting held June 1013, 2013, inChicago, IL. It was issued by the Standards Council on August 1, 2013, with an effective dat

31、e of August21, 2013, and supersedes all previous editions.A tentative interim amendment (TIA) to Sections 516.3 and 516.10 was issued on August 1, 2013.For further information on tentative interim amendments, see Section 5 of the NFPA RegulationsGoverning Committee Projects available at: http:/www.n

32、fpa.org/assets/files/PDF/CodesStandards/TIAErrataFI/TIARegs.pdf.This edition of NFPA 70 was approved as an American National Standard on August 21, 2013.History and Development of the National Electrical CodeThe National Fire Protection Association has acted as sponsor of the National Electrical Cod

33、e since1911. The original Code document was developed in 1897 as a result of the united efforts of variousinsurance, electrical, architectural, and allied interests.In accordance with the provisions of the NFPA Regulations Governing Committee Projects, aNational Electrical Code Committee Report on P

34、roposals containing proposed amendments to the 2011National Electrical Code was published by NFPA in July 2012. This report recorded the actions of thevarious Code-Making Panels and the Correlating Committee of the National Electrical Code Committeeon each proposal that had been made to revise the 2

35、011 Code. The report was circulated to all membersof the National Electrical Code Committee and was made available to other interested NFPA membersand to the public for review and comment. Following the close of the public comment period, theCode-Making Panels met, acted on each comment, and reporte

36、d their action to the Correlating Com-mittee. NFPA published the National Electrical Code Committee Report on Comments in March 2013,which recorded the actions of the Code-Making Panels and the Correlating Committee on each publiccomment to the National Electrical Code Committee Report on Proposals.

37、 The National Electrical CodeCommittee Report on Proposals and the National Electrical Code Committee Report on Comments werepresented to the 2013 June Association Technical Meeting for adoption.NFPA has an Electrical Section that provides particular opportunity for NFPA members interested inelectri

38、cal safety to become better informed and to contribute to the development of the NationalElectrical Code and other NFPA electrical standards. At the Electrical Section Codes and StandardsReview Session held at the 2013 NFPA Conference and Expo, Section members had opportunity todiscuss and review th

39、e report of the National Electrical Code Committee prior to the adoption of thisedition of the Code by the Association at its 2013 June Technical Session.This 53rd edition supersedes all other previous editions, supplements, and printings dated 1897,1899, 1901, 1903, 1904, 1905, 1907, 1909, 1911, 19

40、13, 1915, 1918, 1920, 1923, 1925, 1926, 1928,1930, 1931, 1933, 1935, 1937, 1940, 1942, 1943, 1947, 1949, 1951, 1953, 1954, 1955, 1956, 1957,1958, 1959, 1962, 1965, 1968, 1971, 1975, 1978, 1981, 1984, 1987, 1990, 1993, 1996, 1999, 2002,2005, 2008, and 2011.This Code is purely advisory as far as NFPA

41、is concerned. It is made available for a wide variety ofboth public and private uses in the interest of life and property protection. These include both use in lawand for regulatory purposes, and use in private self-regulation and standardization activities such asinsurance underwriting, building an

42、d facilities construction and management, and product testing andcertification.NFPA 70, National Electrical Code, NFPA, and National Fire Protection Association are registered trademarks of the National Fire Protection Association, Quincy, Massachusetts, 02169.Contents90 Introduction 7023Chapter 1 G

43、eneral100 Definitions . 7027I. General . 7027II. Over 600 Volts, Nominal . 7035110 Requirements for Electrical Installations . 7036I. General . 7036II. 600 Volts, Nominal, or Less 7040III. Over 600 Volts, Nominal . 7042IV. Tunnel Installations over 600 Volts,Nominal . 7046V. Manholes and Other Elect

44、ricalEnclosures Intended for PersonnelEntry, All Voltages 7047Chapter 2 Wiring and Protection200 Use and Identification of GroundedConductors 7049210 Branch Circuits . 7051I. General Provisions . 7051II. Branch-Circuit Ratings 7057III. Required Outlets 7060215 Feeders . 7064220 Branch-Circuit, Feede

45、r, and ServiceCalculations 7066I. General . 7066II. Branch-Circuit Load Calculations . 7067III. Feeder and Service Load Calculations 7069IV. Optional Feeder and Service LoadCalculations 7073V. Farm Load Calculations . 7076225 Outside Branch Circuits and Feeders . 7076I. General . 7076II. Buildings o

46、r Other Structures Suppliedby a Feeder(s) or Branch Circuit(s) 7079III. Over 1000 Volts 7081230 Services 7083I. General . 7083II. Overhead Service Conductors 7084III. Underground Service Conductors . 7086IV. Service-Entrance Conductors . 7086V. Service Equipment General . 7089VI. Service Equipment D

47、isconnectingMeans . 7089VII. Service Equipment OvercurrentProtection . 7091VIII. Services Exceeding 1000 Volts,Nominal . 7093240 Overcurrent Protection . 7094I. General . 7094II. Location 7098III. Enclosures . 70101IV. Disconnecting and Guarding . 70101V. Plug Fuses, Fuseholders, and Adapters . 7010

48、1VI. Cartridge Fuses and Fuseholders 70102VII. Circuit Breakers 70102VIII. Supervised Industrial Installations . 70104IX. Overcurrent Protection over 1000 Volts,Nominal . 70105250 Grounding and Bonding . 70106I. General . 70106II. System Grounding 70109III. Grounding Electrode System andGrounding El

49、ectrode Conductor 70117IV. Enclosure, Raceway, and Service CableConnections 70122V. Bonding 70122VI. Equipment Grounding and EquipmentGrounding Conductors . 70126VII. Methods of Equipment Grounding 70131VIII. Direct-Current Systems 70134IX. Instruments, Meters, and Relays . 70135X. Grounding of Systems and Circuits ofover 1000 Volts 70136280 Surge Arresters, Over 1000 Volts 70139I. General . 70139II. Installation . 70139III. Connecting Surge Arresters . 70140285 Surge-Protective Devices (SPDs), 1000Volts or