1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA ICS 20-2009 (R2015)Informational Guide toElectrical IndustrialTopicsNEMA Standards Publication ICS 20-2009 (R2015) Informational Guide to Electrical Industrial Topics Published by National Electrical Manufacturers Associatio
2、n 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org 2009 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 Wor
3、ks, and the International and Pan American copyright conventions. 2009 National Electrical Manufacturers Association 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 document at the t
4、ime it was developed. Consensus does not necessarily mean that there is unanimous agreement among every person participating in the development of this document. NEMA standards and guideline publications, of which the document contained herein is one, are developed through a voluntary consensus stan
5、dards 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 fairness in the development of consensus, it does not write the
6、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 personal injury, property, or other damages of any nature whatsoe
7、ver, 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, express or implied, as to the accuracy or completeness of any information publis
8、hed 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 products or services by virtue of this standard or guide. In pub
9、lishing 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 else. Anyone using this document should rely on his or her own in
10、dependent 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 be available from other sources, which the user may wish to consu
11、lt 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, designs, or installations for safety or health purposes. Any certific
12、ation 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. NEMA ICS 20-2009 (R2015) Page i 2009 National Electrical Manufacturers Association CON
13、TENTS Foreword . ii Section 1 Comparison of UL 50/UL 50E to IEC 60529 Enclosure Type Ratings . 1 Section 2 Guide to IEC Utilization Categories and UL Ratings for Motor Controllers 5 Section 3 Motors Design IEC vs. NEMA . 8 Section 4 Wire Sizing in Accordance with IEC Standards 12 Section 5 Applicati
14、on Considerations for UL Combination Starters 13 Section 6 NEC 430 Part IX, and Section 430-109 Motor Circuit Switch vs. Motor Disconnects 17 Section 7 Understanding Protection Requirements of the National Electrical Code 21 Section 8 Feeder and Branch Circuits 29 NEMA ICS 20-2009 (R2015) Page ii 20
15、09 National Electrical Manufacturers Association FOREWORD As a result of increased activity in the field of harmonization, primarily involving North American and IEC based standards for electrical equipment, new topics and terminology continue to surface that are increasingly confronting the public
16、and users at large, but which may not be clearly understood. This informational guide was created to provide additional background information on various key topics of interest related to the application and proper usage of electrical equipment in the global marketplace. The topics in this document
17、do not contain all the details and variations of all the mentioned equipment. However, Standard and Code references have been included in the different sections with the intent that users reference them as necessary. In addition, we recommend that you contact the product manufacturer for any product
18、-specific questions that are not covered in this informational guideline. Referenced Standards are intended to be those of the latest revision or latest edition. NEMA publications are subject to periodic review. Any comments or proposed revisions to this guide should be submitted to: Senior Technica
19、l Director, Operations National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 This Standards Publication was developed by the Industrial Automation Control Products and Systems Section. Section approval of the standard does not necessarily imply that
20、all section members voted for its approval or participated in its development. At the time it was approved, the Group/Section was composed of the following members: A B B In c . E ato n E lec tr ic Car lo Gav az z i A uto m ati on Com po ne nts O m ron E lec tr on ic s LL CCoop er Bu s s m an n P ho
21、 en ix Con tac t, I nc .Cum m ins , In c . P os t G lov er Res is tors , In c .E ato n E lec tr ic al , In c . Rel ian c e Co ntrol s Corpor ati onE lec tr o S w itc h Co rpo rati on Roc k w el l A uto m ati onE m ers on E lec tr ic Co. Rus s el ec tr ic , In c .E v erli te Hy brid In du s tr ies In
22、 c . S E W -E urodr iv e, Inc .GE S iem en s In du s tr y , In c .Hubb el l In c orpor ate d S qu are D Com pa nyJ os ly n Cl ark Con tr ol s , In c . T orna T ec h I nc .L-3 Com m un ic ati on s , P ow er Pa rag on T os hi ba In ternati on al Corpor ati onMa s ter Control S y s tem s , In c . T y c
23、 o E lec tr on ic s /A MPMe tr on , In c . W A G O Corpor ati onMi ts ub is hi E lec tr ic A uto m ati on , In c . Y as k aw a E lec tr ic A m eric a, Inc . NEMA ICS 20-2009 (R2015) Page 1 2009 National Electrical Manufacturers Association Section 1 COMPARISON OF UL 50/UL 50E TO IEC 60529 ENCLOSURE
24、TYPE RATINGS UL 50/UL 50E type ratings account for intended indoor and outdoor environmental conditions such as dripping water, dust, hose-directed oil and water, rain, ice formation, and enclosure material ability to withstand rusting and UV exposure. UL 50/UL 50E has construction and performance r
25、equirements relative to enclosure construction that are not contained in IEC 60529 such as metal type, thicknesses, door/cover applicability, hinge design, knockouts, gasket material, corrosion protection methods. UL type enclosure ratings are applicable to enclosures and enclosed type products only
26、. UL does not equate Type Ratings to IP ratings. Appendix A of NEMA 250 does have a table equating NEMA Type Ratings to IP Ratings. There are also numerous other publications and internet sites that provide comparisons between Type Ratings and IP ratings. The IEC designation consists of the letters
27、IP followed by two numerals. The first characteristic numeral indicates the degree of protection provided by the enclosure with respect to persons and solid foreign objects entering the enclosure. The second characteristic numeral indicates the degree of protection provided by the enclosure with res
28、pect to the harmful ingress of water. Additional suffix letters may be specified to denote a higher degree of protection against access to hazardous parts than what is specified by the first numeral. Supplementary letters may also be specified to denote protection under specific conditions (e.g., sp
29、ecified weather conditions, high voltage apparatus). IP codes are applicable to both open type and enclosed type products. IEC 60529 Ingress Protection IP codes account for protection against ingress of objects (e.g., dust, wire, finger, fist) and water (e.g., sprinkler, hose) and optionally may acc
30、ount for protection against impact to the enclosure. IEC 60529 does not specify degrees of protection against damage of equipment, risk of explosions, or conditions such as moisture (produced for example by condensation) or corrosive vapors. IEC requirements for enclosure construction are typically
31、contained in the product standards. NEMA ICS 20-2009 (R2015) Page 2 2009 National Electrical Manufacturers Association UL 50 enclosure type ratings are designated by number as noted in the following table. Table 1-1 UL 50 ENCLOSURE TYPE RATINGS 1 Indoor use primarily to provide a degree of protectio
32、n against limited amounts of falling dirt. 2 Indoor use primarily to provide a degree of protection against limited amounts of falling water and dirt. 3 Outdoor use primarily to provide a degree of protection against rain, sleet, wind blown dust and damage from external ice formation. 3R Outdoor use
33、 primarily to provide a degree of protection against rain, sleet, and damage from external ice formation. 3S Outdoor use primarily to provide a degree of protection against rain, sleet, windblown dust and to provide for operation of external mechanisms when ice laden. 4 Indoor or outdoor use primari
34、ly to provide a degree of protection against windblown dust and rain, splashing water, hose-directed water and damage from external ice formation. 4X Indoor or outdoor use primarily to provide a degree of protection against corrosion, windblown dust and rain, splashing water, hose-directed water, an
35、d damage from external ice formation. 5 Indoor use primarily to provide a degree of protection against settling airborne dust, falling dirt, and dripping noncorrosive liquids. 6 Indoor or outdoor use primarily to provide a degree of protection against hose-directed water, and the entry of water duri
36、ng occasional temporary submersion at a limited depth and damage from external ice formation. 6P Indoor or outdoor use primarily to provide a degree of protection against hose-directed water, the entry of water during prolonged submersion at a limited depth and damage from external ice formation. 12
37、, 12K Indoor use primarily to provide a degree of protection against circulating dust, falling dirt, and dripping noncorrosive liquids. 13 Indoor use primarily to provide a degree of protection against dust, spraying of water, oil, and noncorrosive coolant. NEMA ICS 20-2009 (R2015) Page 3 2009 Natio
38、nal Electrical Manufacturers Association IP code ratings are designated as follows: IP X X X First Index Foreign Bodies Protection, Solids Index Protection against hazardous parts Protection against solid objects (foreign bodies) 0 No special protection 1 Back of hand 50 mm sphere shall not fully pe
39、netrate Large foreign bodies, diam. 50 mm 2 Finger 12.5 mm sphere shall not fully penetrate Medium-sized foreign bodies, diam. 12 mm 3 Tools 2.5 mm sphere shall not penetrate at all Small foreign bodies, diam. 2.5 mm 4 Wires 1.0 mm probe shall not penetrate at all Granular foreign bodies, diam. 1 mm
40、 5 Wires 1.0 mm probe shall not penetrate at all Dust-protected; dust deposits are permitted, but their volume must not affect the function of the unit or impair safety 6 Wires 1.0 mm probe shall not penetrate at all Dust-tight Second Index Water Protection, Liquids Index Protection against water Pr
41、otection from condition 0 No special protection 1 Water dripping/falling vertically Condensation/Light rain 2 Water sprayed at an angle (up to 15 from the vertical) Light rain with wind 3 Spray water (any direction up to 60 from the vertical) Heavy rainstorm 4 Spray water from all directions, (limit
42、ed ingress permitted) Splashing 5 Low pressure water jets from all directions, (limited ingress permitted) Hose down, residential 6 High pressure jets from all directions, (limited ingress permitted) Hose down, commercial. 7 Temporary immersion, 15 cm to 1m Temporary Immersion 8 Permanent Immersion,
43、 under pressure Continuous immersion NEMA ICS 20-2009 (R2015) Page 4 2009 National Electrical Manufacturers Association Third Index Additional Protection from Hazardous Parts Index Protection against impact Equivalent mass impact A Back of hand Large foreign bodies, diam. 50 mm B Finger Medium-sized
44、 foreign bodies, diam. 12.5 mm C Tools with a thickness 2.5 mm Small foreign bodies, diam. 2.5 mm D Wires with a thickness 1 mm Granular foreign bodies, diam. 1 mm Fourth Index Supplementary Protection Index Significance H High-voltage apparatus M Protection against ingress of water when moveable pa
45、rts of equipment are in motion S Protection against ingress of water when moveable parts of equipment are stationary W Protection against specified weather conditions provided with additional protective features or processes Reference Documents: UL 50E Enclosures for Electrical Equipment, Environmen
46、tal Considerations CSA C22.2 No. 94-1 Enclosures for Electrical Equipment, Non-Environmental Considerations NEMA 250 Enclosures for Electrical Equipment (1000 V Maximum) IEC 60529 Degrees of protection provided by enclosures (IP Code) NoteThis is a guide, and standards continuously change; always re
47、fer to the latest revision of the applicable standards for current requirements. NEMA ICS 20-2009 (R2015) Page 5 2009 National Electrical Manufacturers Association Section 2 GUIDE TO IEC UTILIZATION CATEGORIES AND UL RATINGS FOR MOTOR CONTROLLERS Summary: The purpose of this section is to compare th
48、e utilization categories in IEC to Underwriters Laboratories application ratings and definite purpose ratings for motor controllers in order to: Facilitate harmonization (possible adoption of utilization categories by UL) Provide a tool to do one test to obtain ratings under IEC and UL. Typical meth
49、ods to perform one set of tests to obtain multiple ratings are called “umbrella” tests. This involves picking the worst case test parameters and conditions and combining them into one set of tests. While this reduces the number of tests, very often the combined worst case conditions are more severe than the test device can withstand. In some cases, there are minor differences that can easily be accounted for. In other cases, there are differences in test parameters that can be accounted for in an “umbrella” test. Lastly, there are categories that have s
