1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA WC 73-2000 (R2012)Wire Selection Guidelines for Wires Rated at 200-450 CNEMA WC 73-2000 (R2005, R2012) Wire Selection Guidelines for Wires Rated at 200-450o C Published by: National Electrical Manufacturers Association 1300
2、North 17th Street 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 Berne Convention for the Protection of Literary and Artistic Works
3、, and the International and Pan American Copyright Conventions. NEMA WC 73-2000 (R2005, R2012) Page ii Copyright 2012 by the National Electrical Manufacturers Association NOTICE AND DISCLAIMER The information in this publication was considered technically sound by the consensus of persons engaged in
4、 the development and approval of the document 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 pub
5、lications, of which the document contained herein 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
6、 process and establishes rules to promote fairness 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 public
7、ations. NEMA disclaims liability for any personal 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
8、 no guaranty or warranty, express or implied, 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
9、of any individual manufacturer or sellers 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
10、 owed by any person or entity to someone else. 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 t
11、he topic covered by this publication may be 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
12、 certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any health or safetyrelated information in this document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker
13、of the statement. WC73-2000 (R2005, R2012) Page iii Copyright 2012 by the National Electrical Manufacturers Association FOREWORD This standard has been developed by the WC 73 task force under the Electronics/Communications and Control Cable Subcommittee (members as listed below) of the High Performa
14、nce Wire and Cable Section of NEMA in close coordination between manufacturers, users, third party certifying agencies and others having specialized experience. The High Performance Wire and Cable Section of NEMA periodically reviews this standard for any revisions necessary to keep it up to date. P
15、roposed revisions or comments should be submitted to: Senior Technical Director, Operations National Electrical Manufacturers Association 1300 North 17th Street Rosslyn, VA 22209 At the time of reaffirmation, the section comprised the following companies: AFC Cable Systems New Bedford, MA Apical Div
16、ision, Kaneka Texas Corporation El Dorado, AR Belden Inc. St. Louis, MO Cable USA LLC. Naples, FL Champlain Cable Corporation Colechester, VT Coleman Cable Inc. Waukegan, IL Freeport McMoRan Copper and Gold Phoenix, AZ General Cable Highland Heights, KY Harbour Industries LLC. Shelburne, VT IWG High
17、 Performance Conductors Inman, SC The Monroe Cable Corporation, Inc. Middletown, NY Nexans AmerCable Houston, TX The Okonite Company Ramsey, NJ Quirk Wire Company, Inc. West Brookfield, MA Rubadue Wire Company Greeley, CO RSCC Aerospace and Defense East Granby, CT Southwire Company Carrollton, GA Th
18、e Monroe Cable Company, Inc. Middletown, NY TE Connectivity Menlo Park, CA WireMasters, Inc. Columbia, TN This standard was developed with the participation of members from The Committee on Mold Safety of the Society of the Plastics Industry, Washington, D.C. WC 73-2000 (R2005, R2012) Page iv Copyri
19、ght 2012 by the National Electrical Manufacturers Association TABLE OF CONTENTS Page FOREWORD . iii Section 1 SCOPE 1 Section 2 REFERENCED STANDARDS . 4 Section 3 BACKGROUND 5 Section 4 DESCRIPTION OF CONDUCTORS 6 4.1 CONDUCTOR COMPOSITION 6 4.2 TEMPERATURE RANGE . 6 4.3 GAUGE SIZE 6 Section 5 AMPAC
20、ITIES AND CORRECTION FACTORS . 8 5.1 INTRODUCTION . 8 5.2 BASE AMPACITIES 8 5.3 TEMPERATURE CORRECTION FACTORS . 10 5.4 CORRECTION FACTORS FOR MORE THAN THREE CONDUCTORS 11 Section 6 AMPACITY CALCULATION EXAMPLES FROM THE HOT RUNNER INDUSTRY. .12 6.1 BACKGROUND 12 6.2 GENERAL CALCULATION EXAMPLE . 1
21、3 Section 7 SUMMARY AND CONCLUSIONS 12 TABLES 4-1 Temperature Range . 6 4-2 Typical Wire Types . 7 5-1 Allowable Ampacities of Insulated Conductors Rated 0 Through 2000 V, 60 to 90 C (140 to 194 F) Not More Than Three Current-Carrying Conductors in Raceway or Cable or Earth (Directly Buried), Based
22、on Ambient Temperatures of 40 C (104 F) . 8 5-2 Allowable Ampacities of Insulated Conductors Rated 0 Through 2000 V, 60 to 90C (140 to 194 F) Not More Than Three Current-Carrying Conductors in Raceway or Cable or Earth (Directly Buried), Based on Ambient Temperatures of 40 C (104 F) . 9 5-3 Correcti
23、on Factors for Ambient Temperatures Other Than 40 C (104 F), Multiply the Ampacities Shown in Tables 5-1 and 5-2 by the Appropriate Factor Shown Below . 10 5-4 Adjustment Factors for More Than Three Current-Carrying Conductors in a Raceway or Cable (NEC Table 310-15(b)(2)(a) . 11 6-1 Actual Load Bas
24、ed on Number of Conductors . 13 6-2 Wiring Information. 21 FIGURES 1 ACTUAL LOAD BASED ON NUMBER OF CONDUCTORS FOR 12 AWG NCC CLASS 2-10 RATED 250 C . 14 WC73-2000 (R2005, R2012) Page 1 Copyright 2012 by the National Electrical Manufacturers Association Section 1 SCOPE This standard contains guideli
25、nes for calculating amperages and selecting wires for temperatures from 200oto 450o C and for voltage ratings up to and including 1000 volts rms. Ampacity charts, temperature correction factors, and derating factors are provided along with extensive examples of calculations. This information is prov
26、ided to assist the user in their selection of a wire or cable for a particular application. This guideline contains the best engineering estimates for calculation, but it cannot guarantee a successful performance. It is recommended that a trial installation be prepared and appropriate evaluations be
27、 conducted to assure acceptable performance of the completed systems. WC 73-2000 (R2005, R2012) Page 2 Copyright 2012 by the National Electrical Manufacturers Association Section 2 REFERENCED STANDARDS American Society for Testing and Materials (ASTM) 100 Barr Harbor Drive West Conshohocken, PA 1942
28、8-2959 ASTM B 160 Standard Specification for Nickel Rod and Bar ASTM B 298 Standard Specification for Silver-Coated Soft or Annealed Copper Wire ASTM B 3 Soft or Annealed Copper Wire ASTM B 33 Tinned Soft or Annealed Copper Wire for Electrical Purposes ASTM B 355 Standard Specification for Nickel-Co
29、ated Soft or Annealed Copper Wire Canadian Standards Association (CSA) 178 Rexdale Boulevard Etobicoke, ON M9W 1R3 Canada CSA C22.2 #210.2-M90 National Fire Protection Association (NFPA) Batterymarch Park Quincy, MA 02269 ANSI/NFPA-70 National Electrical Code(NEC) NFPA 79 Electrical Standard for Ind
30、ustrial Machinery Underwriters Laboratories Inc. (UL) 333 Pfingsten Road Northbrook, IL 60062 UL 1581 Standard for Electrical Wires, Cables and Flexible Cords WC 73-2000 (R2005, R2012) Page 3 Copyright 2012 by the National Electrical Manufacturers Association Section 3 BACKGROUND This guideline was
31、developed to assist the Mold Makers Division of the Society of Plastics Industry in their goal to provide an engineering baseline for the selection of wires used in the hot runner systems for injection molding equipment. To this end, consideration of amperages, derating factors for number of conduct
32、ors, operating temperatures and overall safe operating conditions must be considered and understood. Most calculations for amperages start with tables developed for wires rated at maximum temperatures of 90 200oC. However, wires used in hot runner systems= are required to operate at temperatures of
33、200 C up to 450 C. Few references cover this higher temperature range. In view of this, it is strongly recommended that the guidelines in this document be verified by trial to assue a safe installation. This guideline provides amperage tables and derating tables from the NECthat can be used by knowl
34、edgeable engineers to calculate current carrying values for high temperature (200 C 450 C) wires and cables. The examples in this standard illustrate how these tables may be used in practice. Also included are various wire types and ratings which may be used for these types of applications. The goal
35、 of this guideline is to assure that a standardized system is used in selecting high temperature wires for hot runner applications. WC 73-2000 (R2005, R2012) Page 4 Copyright 2012 by the National Electrical Manufacturers Association Section 4 DESCRIPTION OF CONDUCTORS 4.1 CONDUCTOR COMPOSITION Bare
36、Copper (BC) Tin Coated Copper (TCC) Silver Coated Copper (SCC) Nickel Coated Copper Class 2 Class 10 (2%10%) (NCC) Nickel Coated Copper Class 27 “A” nickel 4.2 TEMPERATURE RANGE Table 4-1 TEMPERATURE RANGE Material Temperature Range Reference Bare Copper, Tin-Coated Copper1, and Silver-Coated Copper
37、 200oC ASTM B3, ASTM B33, ASTM B298, UL 1581, CSA C22.2 #210.2-M90 Nickel-Coated Copper2250oC ASTM B355, UL 1581, CSA C22.2 #210.2-M90 Class 27 Nickel-Coated Copper 450oC ASTM B355, UL 1581, CSA C22.2 #210.2-M90 “A” Nickel 450oC ASTM B160, UL 1581, CSA C22.2 #210.2-M90 Notes: 1With strand size equal
38、 to or larger than 0.015 inches. 2Nickel Coated Copper Class 2, Class 10 (2%10%) (NCC). 4.3 GAUGE SIZE This guideline covers sizes #24 through #8 AWG. WC 73-2000 (R2005, R2012) Page 5 Copyright 2012 by the National Electrical Manufacturers Association Table 4-2 TYPICAL WIRE TYPES Wire Temperature Co
39、nductor Insulation Generic Rating Composition* Material(s) Designation 200oC BC, TCC, NCC Class 2-10 FEP FEP SCC ETFE ETFE PTFE PTFE Unbraided Silicone Rubber BSR Silicone Rubber/Glass Braid SF Types Polyimide/FEP Tape KF/KFF 250oC NCC Class 2 - 10 PFA PFA MFA MFA PTFE PTFE Unbraided Silicone Rubber
40、 BSR Silicone Rubber/Glass Braid SF Types PTFE/Glass/Glass Braid TGGT PTFE/Ceramic/Glass Braid TCGT PTFE/Aramid/Glass Braid TKGT Polyimide/PTFE Tape - Polyimide/Glass Braid KGT 450oC NCC Class 27, ”A” nickel Mica/Glass Braid MGT Mica/Glass Braid /SS Shield MGT-Shield * Per paragraph 4.1. WC 73-2000
41、(R2005, R2012) Page 6 Copyright 2012 by the National Electrical Manufacturers Association Section 5 AMPACITIES AND CORRECTION FACTORS 5.1 INTRODUCTION Establishing ampacity ratings is an inexact procedure. These tables should only be used as a starting point when establishing ratings for any given s
42、ituation. Values may be lesser or greater than those given in the tables because of the influence of installation method, environment, number of conductors, conductor composition and size, ambient temperatures, insulation types, etc. It is recommended that design engineers desiring accurate ampacity
43、 data closely study the 1999 National Electrical CodeArticles 310-15 through 310-84. Additional information can be derived from AIEE 57-660 “The Calculation of the Temperature Rise and Load Capability of Cable Systems“ by J. H. Neher and M. H. McGrath. This paper was presented to the AIEE general me
44、eting in Montreal, Quebec, Canada on June 24-28, 1957 and was published in the “AIEE Transactions,“ Part 3 (power apparatus and systems), Volume 76, October, 1957, pp. 752-772. The information contained therein is still applicable. The following tables are to be used in series to determine a wires a
45、mpacity in a given application. Reference section 6 for examples of applications of these tables. 5.2 BASE AMPACITIES Table 5-1 ALLOWABLE AMPACITIES OF INSULATED CONDUCTORS RATED 0 THROUGH 2000 VOLTS, 60oTO 90o C (140oTO 194oF) NOT MORE THAN THREE CURRENT-CARRYING CONDUCTORS IN RACEWAY OR CABLE OR E
46、ARTH (DIRECTLY BURIED), BASED ON AMBIENT TEMPERATURES OF 40o C (104o F) AWG 150oC3BC, TCC 200oC BC, TCC, SCC, or NCC 2%-10% 250oC NCC 2%-10% 250oC “A“ Nickel 450oC NCC-Class 27 450oC “A“ Nickel 24 6.6 7.2 8 4 9 4.3 22 9 9.6 10.8 5 12 5.6 20 13 14 15 7 18 8 18 17 18 20 9.4 23 11 16 22 24 26 12 30 14
47、14434 36 39 18 45 21 12 43 45 54 25 56 26 10 55 60 73 34 75 35 8 76 83 93 43 104 49 Notes: 3This column is for reference purposes only. 414-8 AWG 150-150 NCC data is from NEC Table 310-18. WC 73-2000 (R2005, R2012) Page 7 Copyright 2012 by the National Electrical Manufacturers Association Table 5-2
48、ALLOWABLE AMPACITIES OF INSULATED CONDUCTORS RATED 0 THROUGH 2000 V, 60oTO 90o C (140oTO 194oF) NOT MORE THAN THREE CURRENT-CARRYING CONDUCTORS IN RACEWAY OR CABLE OR EARTH (DIRECTLY BURIED), BASED ON AMBIENT TEMPERATURES OF 40oC (104oF)5 AWG 150o C BC, TCC 200o C BC, TCC, SCC, or NCC 2%-10% 250oC N
49、CC 2%-10% 250oC “A“ Nickel 450o C NCC-Class 27 450oC “A“ Nickel 6696 110 117 55 138 65 4 120 125 148 69 162 76 3 143 152 166 78 182 85 2 160 171 191 90 210 99 1 186 197 215 101 236 110 1/0 215 229 244 114 268 126 2/0 251 260 273 128 300 141 3/0 288 297 308 144 338 159 4/0 332 346 361 169 397 186 250 365 385 398 187 - - 300 414 436 452 212 - - 350 461 486 503 236 - - 400 495 522 540 254 - - 500 563 593 613
