1、 NEMA RV 2 APPLICATION AND INSTALLATION GUIDELINES FOR NONMETALLIC-SHEATHED CABLE AND UNDERGROUND FEEDER AND BRANCH CIRCUIT CABLE NEMA Standards Publication RV 2-2011 Application and Installation Guidelines for Nonmetallic-Sheathed Cable and Underground Feeder and Branch Circuit Cable Published by:
2、National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22209 www.nema.org Copyright 2011 by the National Electrical Manufacturers Association. All rights including translation into other languages, reserved under the Universal Copyright Convention, the Ber
3、ne Convention for the Protection of Literary and Artistic Works, and the International and Pan American Copyright Conventions. NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in the development and approval of the documen
4、t at the time it was developed. Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document contained h
5、erein is one, are developed through a voluntary consensus standards development process. This process brings together volunteers and/or seeks out the views of persons who have an interest in the topic covered by this publication. While NEMA administers the process and establishes rules to promote fa
6、irness in the development of consensus, it does not write the document and it does not independently test, evaluate, or verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any per
7、sonal injury, property, or other damages of any nature whatsoever, whether special, indirect, consequential, or compensatory, directly or indirectly resulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, expressed or impli
8、ed, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty that the information in this document will fulfill any of your particular purposes or needs. NEMA does not undertake to guarantee the performance of any individual manufacturer or sellers
9、products or services by virtue of this standard or guide. In publishing and making this document available, NEMA is not undertaking to render professional or other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone e
10、lse. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. Information and other standards on the topic covered by this publication may b
11、e available from other sources, which the user may wish to consult for additional views or information not covered by this publication. NEMA has no power, nor does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, desig
12、ns, or installations for safety or health purposes. Any certification or other statement of compliance with any health or safety-related information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. RV 2-2011 Page i CONTEN
13、TS Forewordiii Section 1 APPLICATION GUIDELINES FOR NONMETALLIC-SHEATHED CABLE. 1 1.1 Construction. 1 1.1.1 General 1 1.1.2 Circuit Conductors. 1 1.1.3 Grounding Conductor 1 1.1.4 Cable Sheath 1 1.2 Grounding 2 1.3 Marking and Identification 2 1.3.1 Finished Cable 2 1.3.2 Grounding Conductors 2 1.3.
14、3 Size Identification 2 1.4 Codes and Standards 2 1.4.1 National Electrical Code 2 1.4.2 Underwriters Laboratories Inc. (UL) Standards and Directories. 5 Section 2 APPLICATION GUIDELINES FOR UNDERGROUND FEEDER AND BRANCH CIRCUIT CABLE 8 2.1 Construction. 8 2.1.1 General 8 2.1.2 Circuit Conductors. 8
15、 2.1.3 Grounding Conductors 8 2.1.4 Cable Sheath 8 2.2 Grounding 9 2.3 Marking and Identification 9 2.3.1 Finished Cable 9 2.3.2 Grounding Conductors 9 2.3.3 Jacket Color 9 2.4 Codes and Standards 9 2.4.1 National Electrical Code 9 2.4.2 UL Standards and Directories. 11 Section 3 INSTALLATION GUIDEL
16、INES FOR NONMETALLIC-SHEATHED CABLE AND UNDERGROUND FEEDER AND BRANCH-CIRCUIT CABLE. 14 3.1 General 14 3.2 Inserting the Cable 14 3.3 Cable Preparation 14 3.4 Seating a Securement Clamp 14 3.5 Screw Tightening Torque 14 3.6 Supports 15 3.6.1 Required Intervals . 15 3.6.2 Installation in Metal Framin
17、g Members . 15 3.6.3 Installation in Wood Framing Members 15 3.7 Securing NM-B or UF-B at Nonmetallic Boxes Without Cable Clamps. 16 3.8 Underground Installations for UF-B. 16 3.9 Special Installation Considerations . 16 3.9.1 Exposed Work. 16 3.9.2 Unfinished Basements and Crawl Spaces 16 3.9.3 Acc
18、essible Attics . 16 3.9.4 Corrosive Locations 16 3.9.5 Solar Photovoltaic Systems 16 3.10 Bending Radius . 17 3.11 Unsupported Cable 17 Copyright 2011 by the National Electrical Manufacturers Association. RV 2-2011 Page ii 3.12 Ampacity 17 3.13 Damage . 17 3.13.1 Physical Damage 17 3.13.2 Flood Dama
19、ge. 17 3.14 Verification of Installation. 17 TABLES 1-1 Grounding Conductors in NM-B Cables with 2, 3, or 4 Circuit Conductors 1 2-1 Grounding Conductors in UF-B Cables with 2, 3, or 4 Circuit Conductors . 8 FIGURES 3-1 Common Cable Support and Protection Product 19 3-2 Positioning Cables Under Stap
20、les.20 Copyright 2011 by the National Electrical Manufacturers Association. RV 2-2011 Page iii Foreword These application and installation guidelines offer practical information on correct usage and industry recommended practices for the installation of Type NM-B nonmetallic-sheathed cable and Type
21、UF-B underground feeder and branch circuit cable in accordance with the National Electrical Code. These guidelines have been developed by the NEMA Building Wire and Cable Group and Dues Center, which has committed to periodically reviewing them for any revisions necessary to address changing conditi
22、ons, product listing and installation requirements, and technical progress. Comments for proposed revisions are welcomed and should be submitted to: Vice President, Technical Services National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, VA 22209 At the time of ap
23、proval, the Building Wire and Cable Group and Dues Center of the National Electrical Manufacturers Association had the following members: Alan Wire CompanySikeston, MO Alcan CableAtlanta, GA AmercableEl Dorado, AR Atkore AFC Cable SystemsNew Bedford, MA Cerro Wire LLCHartselle, AL Colonial Wire Cond
24、uit Bodies; Fittings; and Handhole Enclosures 314.17 Conductors Entering Boxes, Conduit Bodies or Fittings Article 334Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS Copyright 2011 by the National Electrical Manufacturers Association. RV 2-2011 Page 4 Article 392Cable Trays 392.3 Uses Permitted E
25、quipment for General Use Article 410 Luminaries, Lampholders, and Lamps 410.24 Connection of Electric-Discharge Lighting Fixtures Special Occupancies Article 518Assembly of Occupancies 518.4 Wiring Methods Article 520Theaters, Audience Areas of Motion Picture and TV Studios, Performance Areas, and S
26、imilar Locations 520.5(c) Wiring Methods Article 550Mobile Homes, Manufactured Homes, and Mobile Home Parks 550.15 Wiring Methods and Materials Article 551Recreational Vehicles and Recreational Vehicle Parks 551.20 Combination Electrical Systems 551.47 Wiring Methods 551.55 Interior Equipment Ground
27、ing Article 552Park Trailers 552.10 Low Voltage Systems 552.48 Wiring Methods 552.56 Interior Equipment Grounding Special Conditions Article 725Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits 725.136 Separation from Electric Light, Power, Class 1, NPLFA Circuit Co
28、nductors, and Medium Power Network-Powered Broadband Communication Cables 725.179 Listing and Marking of Class 2, Class 3, and Type PLTC Cables Article 760.136 Separation from Electric Light, Power, Class 1, NPLFA, and Medium Power Network-Powered Broadband Communications Circuit Conductors Communic
29、ations Systems Article 800Communications Circuitry 800.133 Installation of Communications Wires, Cables, and Equipment Article 830Network Powered Broadband Communications Systems 830.133 Installation of Network-Powered Broadband Communications, Cables, and Equipment Reprinted with permission from NF
30、PA 70-2011, the National Electrical Code, Copyright 2010, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the referenced subject, which is represented only by the standard in its entirety. Copyright 2011 by the National Electrical Manufacturers Association. RV
31、2-2011 Page 5 1.4.2 Underwriters Laboratories Inc. (UL) Standards and Directories UL publishes a number of standards and directories that provides detailed information on the construction, performance, application, ratings, and installation aspects of Type NM-B cable. 1.4.2.1 Standards The UL standa
32、rd for the construction and performance of Type NM-B cable is UL 719. According to NEC Section 334.112, the insulated conductors for NM-B cable must be of the types listed in Table 310.104(A), or one identified for use in this cable. Currently, all Type NM-B cable contains THHN-style conductors. TW
33、style conductors have been used in the past, and are permitted by UL 719, but are not presently used. 1.4.2.2 Directories UL publishes several directories that contain useful information on the products that it lists, recognizes, and certifies. Installers and inspection authorities use these directo
34、ries frequently to gain a better understanding of how to specify and install products in accordance with their listing, and to demonstrate that a product is UL listed. These directories are helpful tools for understanding the details of how products, in this case Type NM-B cable, are constructed and
35、 marked as well as information on special or optional ratings, and terminations. One of the directories covers the UL approved methods for maintaining the fire resistive rating on walls, floors, and ceilings for fire-resistance rated construction, when cables must penetrate them and be fire stopped.
36、 1. UL General Information for Electrical Equipment DirectoryWhite Book The following information on Type NM Cable is reprinted from the UL Guide Information for Electrical Equipment, The White Book 2010, with permission from Underwriters Laboratories Inc., Copyright 2010 Underwriters Laboratories I
37、nc. Update to the latest UL Directory: http:/ USE This category covers Types NM-B and NMC-B nonmetallic-sheathed cable, rated 600 V, intended for use in accordance with Article 334 of ANSI/NFPA 70, National Electrical Code (NEC), and Listed in copper sizes 14 to 2 AWG inclusive and aluminum or coppe
38、r-clad aluminum sizes 12 to 2 AWG inclusive. This cable contains conductors rated 90C; however, the ampacities of the cable are those of 60C conductors as specified in Article 334 and Table 310.16 of the NEC. PRODUCT MARKINGS Cable with copper-clad aluminum conductors is surface marked AL (CU-CLAD)
39、or Cu-clad Al, and cable with aluminum conductors is surface marked AL. Wire and cable employing compact-stranded copper conductors is so identified directly following the conductor size, wherever it appears (surface, tag, carton or reel), by compact copper. The abbreviations CMPCT and CU may be use
40、d for compact and copper, respectively. Tags, reels and cartons for products employing compact-stranded copper conductors have the marking: Terminate with connectors identified for use with compact-stranded copper conductors. Cable suitable for use in cable trays is appropriately marked. Cable marke
41、d for cable tray use may also have a supplementary sunlight resistant marking. Cable that complies with the Limited Smoke Test requirements specified in UL 1685, Vertical-Tray Fire-Propagation and Smoke-Release Test for Electrical and Optical-Fiber Cables, is surface marked ST1. ADDITIONAL INFORMATI
42、ON For additional information, see Electrical Equipment for Use in Ordinary Locations (AALZ). Copyright 2011 by the National Electrical Manufacturers Association. RV 2-2011 Page 6 REQUIREMENTS The basic standard used to investigate products in this category is ANSI/UL 719, Nonmetallic-Sheathed Cable
43、s. UL MARK The UL symbol on the product and the Listing Mark of Underwriters Laboratories Inc. on the attached tag, coil, reel or smallest unit container in which the product is packaged is the only method provided by UL to identify these products manufactured under its Listing and Follow-Up Service
44、. The Listing Mark for these products includes the UL symbol (as illustrated in the Introduction of this Directory) together with the word LISTED, a control number, and the product name as appropriate: Nonmetallic-sheathed cable that contains copper or copper-clad aluminum conductors has the product
45、 name Nonmetallic-sheathed Cable; nonmetallic-sheathed cable that contains aluminum conductors has the product name Nonmetallic-sheathed Aluminum Cable. 2. UL Electrical Construction Equipment DirectoryGreen Book ULs Electrical Construction Equipment Directory, Green Book, contains the identical inf
46、ormation that is contained in the White Book with the addition of the company name, address, and UL file number of those manufacturers that are authorized by Underwriters Laboratories to produce a listed product. The Green Book is frequently used to identify and locate listed manufacturers of Type N
47、M Cable, to verify if a manufacturer is authorized to produce UL Listed Type NM, and to identify the manufacturer of the cable when the cable is marked with the UL File number (E number) in place of the company name. Green Book information on Type NM Cable (category code PWVX) can be found here or g
48、o to: http:/ for wiring in wet, dry, or corrosive locations; installed as nonmetallic-sheathed cable as a multiconductor cable, in accordance with Article 334 subject to the conductor temperature limitations in Section 310.15(A)(3); in solar photovoltaic systems in accordance with NEC Section 690.31
49、; and in cable trays as a multiconductor construction. 2.4.1.2 Uses Not Permitted Type UF-B cable is not permitted for use as a service-entrance cable, nor for use in commercial garage, theater, motion picture studio, storage battery room, hoistway, elevator, or escalator. Type UF-B is not permitted in any hazard
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