1、NFPA79 Electrical Standard for Industrial Machinery 2015 Edition NFPA, 1 Batterymarch Park, Quincy, MA 02169-7471 An International Codes and Standards Organization 1/14ISBN: 978-145590894-3 (Print)ISBN: 978-145590927-8 (PDF)IMPORTANT NOTICES AND DISCLAIMERS CONCERNING NFPASTANDARDS NOTICE AND DISCLA
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29、t no cost at www.nfpa.org/freeaccess.Copyright 2014 National Fire Protection Association. All Rights Reserved.NFPA79Electrical Standard forIndustrial Machinery2015 EditionThis edition of NFPA 79, Electrical Standard for Industrial Machinery, was prepared by theTechnical Committee on Electrical Equip
30、ment of Industrial Machinery and released by theCorrelating Committee on National Electrical Code. It was issued by the Standards Councilon April 29, 2014, with an effective date of May 19, 2014, and supersedes all previous editions.This edition of NFPA 79 was approved as an American National Standa
31、rd on May 19, 2014.Origin and Development of NFPA 79This standard was first submitted at the 1961 NFPA Annual Meeting under the title Electri-cal Standard for Machine Tools and was tentatively adopted subject to comments. It was exten-sively revised and resubmitted at the 1962 Annual Meeting, where
32、it was officially adopted. In1965 a revised edition was adopted, reconfirmed in 1969, and in 1970, 1971, 1973, 1974, 1977,1980, 1985, 1987, 1991, 1994, 1997, 2002 and 2007, revised editions were adopted.In September 1941, the metalworking machine tool industry wrote its first electrical stan-dard to
33、 make machine tools safer to operate, more productive, and less costly to maintain,and to improve the quality and performance of their electrical components. That particularstandard served as an American “War Standard.”To study the special electrical problems involved with machine tools, in 1941 the
34、 ElectricalSection of the National Fire Protection Association sanctioned a Special Subcommittee onWiring, Overcurrent Protection, and Control of Motor-Operated Machine Tools. This sub-committee, cooperating with machine tool builders, manufacturers of control equipment,and Underwriters Laboratories
35、 Inc., conducted tests and investigated the peculiar conditionsinvolved with machine tools that might warrant exception to certain specific National ElectricalCoderequirements. This investigation resulted, on August 4, 1942, in a Tentative InterimAmendment and first appeared in a 1943 supplement to
36、the 1940 edition of the NationalElectrical Code as Article 670, “Machine Tools.” It remained essentially unchanged through the1959 edition.Meanwhile, manufacturers of other types of industrial equipment erroneously began tofollow the specialized practices permitted by Article 670. Late in 1952, a Te
37、chnical Subcom-mittee on Fundamentals of Electrically Operated Production Machinery and Material Han-dling and Processing Equipment for Fixed Locations was organized to attempt to group thespecial requirements of this broad field into one article. The extremely broad scope intro-duced so many proble
38、ms that, in December 1956, this technical subcommittee was reorga-nized into an NFPA committee whose scope was limited to machine tools and whose objectivewas the preparation of this NFPA standard with corresponding revisions in Article 670 in theNational Electrical Code.Modern machine tool electric
39、al equipment may vary from that of single-motor machines,such as drill presses, that perform simple, repetitive operations, to that of very large, multimo-tored automatic machines that involve highly complex electrical control systems, includingelectronic and solid-state devices and equipment. Gener
40、ally these machines are speciallydesigned, factory wired, and tested by the builder and then erected in the plant in which theywill be used. Because of their importance to plant production and their usually high cost, theyare customarily provided with many safeguards and other devices not often inco
41、rporated inthe usual motor and control application as contemplated by the National Electrical Code.Although these machines may be completely automatic, they are constantly attended,when operating, by highly skilled operators. The machine usually incorporates many specialdevices to protect the operat
42、or, protect the machine and building against fires of electricalorigin, protect the machine and work in process against damage due to electrical failures, andprotect against loss of production due to failure of a machine component. To provide these791NFPA and National Fire Protection Association are
43、 registered trademarks of the National Fire Protection Association, Quincy, Massachusetts 02169.safeguards, it may be preferable to deliberately sacrifice a motor or some other component, rather than to chanceinjury to the operator, the work, or the machine. It is because of such considerations that
44、 this standard varies from thebasic concepts of motor protection as contained in the National Electrical Code.As NFPA 79 evolved, it became apparent that certain classes of light industrial machinery (e.g., small drill presses,bench grinders, sanders, etc.) were not appropriately covered. The 1977 e
45、dition of the standard recognized thisproblem and purposely excluded tools powered by 2 hp or less.Subsequent to publication of the 1977 standard, a light industrial machinery standard development activity wasinitiated by the Power Tool Institute. The 1985 edition of NFPA 79 reflects this activity,
46、and appropriate requirementsare now included in the standard.In 1975, the Society of the Plastics Industry requested that this standard be enlarged in scope to include plasticsmachinery. A formal request was received by NFPA in September 1978, and, through the combined efforts of theNFPA 79 committe
47、e and representatives of the Society of the Plastics Industry, the scope was broadened to include suchmachinery in the 1980 edition.In June 1981, the Joint Industrial Council (JIC) Board of Directors acknowledged the dated state of the electricaland electronic standards and requested that NFPA 79 in
48、corporate into its standard the material and topics covered bythe JIC electrical (EMP-1-67, EGP-1-67) and electronic (EL-1-71) standards with the intention that the JIC standardseventually would be declared superseded. The NFPA Standards Council approved the request with the stipulation thatthe mate
49、rial and topics incorporated from the JIC standards be limited to areas related to electrical shock and firehazards. The 1985 edition reflected the incorporation of the appropriate material from the JIC electrical (EMP-1-67,EGP-1-67) standards not previously covered. The 1991, 1994, and 1997 editions included additional references tointernational standards and reflected the committees efforts in harmonization.The 2002 edition was a major rewrite and represented a significant and historic effort in harmonizing an existingNFPA standard with an existing IEC standard. Major change
