IEEE NESC-2017 en National Electrical Safety Code(R)《国家电气安全规程》.pdf

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1、445 Hoes Lane, Piscataway, NJ 08854 USA | standards.ieee.orgTel. +1 732-981-0060 Fax +1 732-562-15712016 IEEE002-3-16Facebook: ieeesaLinkedIn: Standards Insight blog: YouTube: Google+: with us on: 2017 National Electrical Safety Code (NESC) C2-20172017 NESC Related Products3 Park Avenue, New Yor

2、k, NY 10016-5997, USATHANNIVERSARY EDITION9 781504 419932Product code: STDPT20924ISBN: 978-1-5044-1993-2IEEE NESC2017 AppThe NESC 2017 App available for iOS, Android, and Windows provides easy access to the code via your mobile device or tablet. A great reference source for those in the field, the N

3、ESC 2017 App will include all of the content of the printed Code with enhanced features: Easy access to all Parts including Front Matter of the NESC All referenced diagrams, charts, and drawings Instant access to formulas, equations and calculations withcontext Ability to quickly look up terms using

4、 the Dictionary feature Access to media related to the NESC2017 NESCHandbook, Premier EditionThe 2017 NESC Handbook represents commentary by contributors, and is a next-generation tool for the professional who wants to improve their understanding of the NESC and includes a representation of NESC tex

5、t. It gives users insight into: A history of the NESCs rules How the rules might be applied Interpretations Background interspersed and coincident with the representedportions of Code being discussed and highlighted Responses to change proposals during the past 90 yearsNESCTabsNew for the NESC 2017

6、Edition, this set of 48 durable, self-adhesive tabs is compatible with both the NESC 2017 Edition and 2017 NESC Handbook. The tabs are color-coded to make locating important information fast and easy. The set includes easy-to-affix preprinted press-and-stick tabs and write-your-own blanks. NESCTrain

7、ing CoursesNew courses based on the NESC 2017 Edition: Introduction to the National Electrical Safety Code(NESC) Changes to the NESC2017 Edition NESC2017: Introduction to Grounding NESC2017: Rules for Installation and Maintenance of ElectricSupply Stations NESC2017: Safety Rules for Installation and

8、 Maintenanceof Overhead Electric Supply NESC2017: Safety Rules of the Installation and Maintenanceof Underground Electric Supply NESC2017: Work Rules for the Operation of Electric Supplyand Communications Lines and Equipment.To learn more about the NESC and related products, visit standards.ieee.org

9、/nescAccreditedStandardsCommitteeC2-2017National Electrical Safety CodeSecretariatInstitute of Electrical and Electronics Engineers, Inc.Approved 26 April 2016American National Standards Institute2017 EditionAbstract: This Code covers basic provisions for safeguarding of persons from hazards arising

10、 from theinstallation, operation, or maintenance of (1) conductors and equipment in electric supply stations, and(2) overhead and underground electric supply and communication lines. It also includes work rules for theconstruction, maintenance, and operation of electric supply and communication line

11、s and equipment. TheCode is applicable to the systems and equipment operated by utilities, or similar systems and equipment, ofan industrial establishment or complex under the control of qualified persons. This Code consists of theintroduction, definitions, grounding rules, list of referenced and bi

12、bliographic documents, and Parts 1, 2, 3,and 4 of the 2017 Edition of the National Electrical Safety Code.Keywords: communications industry safety; construction of communication lines; construction of electricsupply lines; electrical safety; electric supply stations; electric utility stations; high-

13、voltage safety; operation ofcommunications systems; operation of electric supply systems; power station equipment; power stationsafety; public utility safety; safety work rules; underground communication line safety; underground electricline safety1 August 2016 STD20924The Institute of Electrical an

14、d Electronics Engineers, Inc.3 Park Avenue, New York, NY 10016-5997, USACopyright 2016 by the Institute of Electrical and Electronics Engineers, Inc.All rights reserved. Published 2016Printed in the United States of AmericaNational Electrical Safety Code and NESC are registered trademarks and servic

15、e marks in the U.S. Patent (978) 750-8400. Permission tophotocopy portions of any individual standard for educational classroom use can also be obtained throughthe Copyright Clearance Center.iiiCopyright 2016 IEEE. All rights reserved.ForewordThis publication consists of the parts of the National El

16、ectrical Safety Code(NESC) (AccreditedStandards Committee C2) currently in effect. Substantive changes in the 2017 Edition are identified by a change bar in the left-hand margin. In severalcases, rules have been relocated without substantive changes in the wording. In these cases, only the rulenumbe

17、rs have been indicated as having been changed.2017 EditionMajor changes in the 2017 Edition include (1) adding definitions for communication and supply space,(2)adding exceptions for underground cable grounding requirements, (3) revising and reorganizing the guyinsulator placement rules, (4) revisin

18、g and reorganizing the Grades of Construction application rules, and(5)revising the Part 4 worker safety rules to align with the changes in the OSHA work rules. In Section 1, the Purpose rule was reorganized to clarify who and what the rules of the Code are meant tosafeguard. The Scope rule was revi

19、sed to include wind and solar energy as one of the sources for generatingelectricity. Two major revisions were added to the Application Rule (Rule 013). The first is the addition toRule 013B3 clarifying which edition of the Code applies after an installation has been updated to asubsequent Code edit

20、ion. The second revision concerns the addition of new facilities to an installation thatdoes not meet Code rules.Definitions for terms no longer used in the Code were deleted. Definitions added include communicationequipment, communication space, electric supply equipment, insulator, limited access

21、highways, supplyspace, wind span, and weight span.In Section 3 (References), standards were added, updated, or deleted if no longer referenced in the Code.Appendix E (Bibliography) was also updated.In Rules 092C1 and 096C, exceptions were added to exempt the four-grounds-in-each mile requirementunde

22、r specific limiting conditions. In Rule 094B, stainless steel was included with nonferrous metals. Manyof the grounding electrodes described in the rule are now considered to be equivalent. The exceptionallowing other dimensions and configurations if supported by aqualified engineering studywas expa

23、nded tocover more types of electrodes.In Part 1, major revisions to electric supply stations consisted of additions to Rule 110A that address safetysign locations, adjoining fence restrictions, and impenetrable fence modifications. Rule 114 pertaining tofire-extinguishing equipment was deleted. Rule

24、 124A1 was revised to require the electric supply stationclearance values in Table124-1 and Table110-1 to have appropriate atmospheric correction factors appliedfor altitudes above 1000 m (3300 ft). Guy insulator Rules 215C2 to 215C8 were rewritten and reorganized to make them easier to understand a

25、ndapply with the voltage transfer rules associated with guy insulators being removed. Voltage addercalculations for vertical clearances between conductors carried on different supporting structures specifiedin Rule 233C will now require using a phasor relationship when determining the voltage betwee

26、n theconductors involved. Clearances of overhead lines from aboveground swimming pools with and withoutdecks were added to Rule 234E1. All the rules associated with the clearances of antennas from supply andcommunication lines were placed into one rule, Rule 235I, and Rule 238E will now require a 1

27、m (40 in)This foreword is not a part of Accredited Standards Committee C2-2017, National Electrical Safety Code.ivCopyright 2016 IEEE. All rights reserved.vertical clearance between luminaires that are not effectively grounded and communication cables andequipment located in the communication space.

28、 NOTEDefinitions of supply and communi cation space are now in Section 2.In general, the rules in Section 24 were edited to provide greater clarity and easier reading. For example,Rule 241C was converted from a paragraph format to a bulleted format and a note was added to Rule 240 topoint out that r

29、equirements for emergency and temporary installations are addressed in Rule 014. Although the content of Table242-1 remains largely the same, the order of the columns and rows waschanged to follow a more intuitive progression. Take note that for crossing supply conductors exceeding22kV, the table va

30、lue is now shown as Grade B and Footnote 3 allows a reduction to Grade C if the supplycircuits will be promptly de-energized. Previously, the Table242-1 showed a requirement of Grade C with afootnote stating that Grade B was required if the supply would not be promptly de-energized. Footnote 11was a

31、lso added to Table242-1 to specify that Grade N construction can be used for dielectric fiber-opticsupply cables when certain grounding requirements are met. Rule 250D has additional language that clarifies the objects that have ice added to them for loading analysisand those objects where ice is no

32、t added. Rule 261H has an added requirement that the potential for damagefrom Aeolian vibration must be considered for all conductors. In addition, when limiting tension is the onlymethod applied for mitigation, initial and final tension limits are specified.Several changes to requirements for insul

33、ators were adopted into Section 27. The industry has developednew insulator ratings over the last 10 years and the changes in Section 27 were made to coincide withmanufacturers current rating practices.Separate allowed percentage of strength ratings are now specified for Rule 250B loads versus Rules

34、 250Cand 250D loads. In addition, new classifications were adopted to differentiate distribution and transmissioninsulators and the allowable values were changed for those insulators that have a new rating methodology. In Part 3, rules requiring underground conductor neutrals and any other conductor

35、s that are intentionallygrounded were revised to require grounding where they are exposed to personnel contact.Rule 354D contains exceptions that allow grounding and bonding between underground communication andsupply cables at equipment locations in lieu of grounding and bonding the underground cab

36、le betweenequipment locations.The rules covering burial depths for direct buried underground cables and duct not part of a conduit systemwere revised to require burial depths; an exception was added if the requirement cannot be met.The conductance requirement in the random separation between supply

37、and communication rules wasdeleted. Several noteworthy changes were made to Part 4. Specifically, revisions to Rule 410A, Rule 420K, Rule441, and the associated tables were adopted to align these work rules with changes to OSHA federalregulations (Title 29 of the Code of Federal Regulations) publish

38、ed in April 2014. Rule 410A3 was revised to recognize the possible necessity to protect the head, face, hand, and feet ofemployees working on or near energized lines, parts, or equipment at voltages 50 V to 800 000 V (ac) andalso includes a recommendation for voltages 50 V to 250 V (dc).Rule 420K wa

39、s revised and expanded to address and provide guidance fall protection and fall arrestequipment and its use. vCopyright 2016 IEEE. All rights reserved.Rule 441 (and the associated tables) was extensively revised to: address situations where the grounding oflines operating at 600 V (ac) or less is im

40、practical; include definitions for reach and extended reach; addresswork on exposed grounded lines 301 V to 72.5 kV (ac); clarify the use of the Rubber Glove Work Methodfor lines 301 V to 72.5 kV (ac); and address work position when performing live-line work on lines 72.5 kVand above. Table441-1 was

41、 revised to include material changes to the default minimum approach distancevalues for ac live-line work for lines 72.6 kV and above. Corresponding to the revisions to Rule 441A4, newTable441-2, Table441-3, and Table441-4 were added to supplement Table441-1 where the per unittransient overvoltage v

42、alue has been determined through an engineering analysis. 2012 EditionIn the 2012 Edition, major changes include: an updated scope, application, and definitions; greatlysimplified minimum approach tables and voltage exposure for arc flash; the addition of K factor for wiretension; and added clarific

43、ation of the ungrounded portions of guys around swimming pools. Consistency tothe application of the terms grounded and effectively grounded was applied. Rule 313 was reworded toinclude the recording and correction of conditions, not just defects, which affects compliance with the Code.A new rule, R

44、ule 355, was added that contains rules for duct not part of a conduit system. Two significantchanges were made to the work rules in Part 4, specifically in the Rule 441 minimum approach distancedtables, and also in Rule 410A3 on arc flash exposure.2007 EditionThe major revisions for the 2007 Edition

45、 included grounding, moving sag calculations to Section 23,moving guy and span wires insulator rules to Section 21, phasing out of the alternate method for load factorsand strength factors, flammable materials transported, phase-to-phase cover-up, and minimum approachdistance tables.2002 EditionIn t

46、he 2002 Edition, several changes were made that affected all or several parts of the Code. Particularly,this edition clarifies interfaces between the NEC and NESC with regard to Code jurisdiction in the area ofstreetlights and area lights. Also included is clarification for situations between utilit

47、y workers and theirauthorized contractors and installations on industrial complexes.1997 EditionIn the 1997 Edition, the most notable general change that took place is that numerical values in the metric(SI) system are shown in the preferred position, with customary inch-foot-pound values (inside pa

48、rentheses)following. A bibliography, Appendix B, which consists of a list of resources identified in notes orrecommendations, was added. Changes were made to rules affecting grounding, electric supply stations, andoverhead lines, particularly with regard to clearance rules applicable to emergency an

49、d temporaryinstallations. Strength requirements contained in Sections 24, 25, and 26 were revised completely.Underground line requirements for random separation for underground lines of direct-buried cables weremodified. The requirement for cable identification marking by means of sequentially placed logos wasintroduced. Work rules added a requirement that warning signs and tags comply w