1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA RN 1-2005 (R2013)Polyvinyl-Chloride (PVC) Externally CoatedGalvanized Rigid SteelConduit and IntermediateMetal ConduitNEMA RN 1-2005 (R2013) Polyvinyl-Chloride (PVC) Externally Coated Galvanized Rigid Steel Conduit and Inter
2、mediate Metal Conduit Published by: National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org 2013 National Electrical Manufacturers Association. All rights, including translation into other languages, reserved under the Universal Copyright
3、Convention, the Berne 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 a consensus among persons engaged in its development at the
4、time it was approved. Consensus does not necessarily mean there was unanimous agreement among every person participating in the development process. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document herein is one, are developed throu
5、gh a voluntary 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. Although NEMA administers the process and establishes rules to promote fairness in the development of consensus,
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7、f any nature, 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 informati
8、on published herein, and disclaims and makes no warranty that the information in this document will fulfill any particular purpose(s) or need(s). NEMA does not undertake to guarantee the performance of any individual manufacturers or sellers products or services by virtue of this standard or guide.
9、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 else. Anyone using this document should rely on his or her
10、own independent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstance. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to
11、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, designs, or installations for safety or health purposes. Any cer
12、tification 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. RN 1-2005 (R2013) Page i 2013 National Electrical Manufacturers Association CONTE
13、NTS Page Foreword . ii Section 1 GENERAL . 1 1.1 Scope 1 1.2 Referenced Standards 1 Section 2 RIGID CONDUIT AND IMC . 3 2.1 Galvanized Rigid Steel Conduit . 3 2.2 Intermediate Metal Conduit . 3 2.3 Interior Coatings 3 2.4 Thread Protectors 3 Section 3 EXTERNAL COATINGS . 4 3.1 Thickness 4 3.2 Coatin
14、g Material 4 3.3 Application of Coating 4 3.3.1 Cleaning 4 3.3.2 Priming 4 3.3.3 Coating 4 3.4 Elbows . 4 3.5 Couplings. 4 3.6 Workmanship and Appearance . 5 3.7 Performance Requirements 5 3.8 Adhesion 5 Section 4 CORROSION RESISTANT INTERNAL COATINGS (OPTIONAL) 6 4.1 Thickness 6 4.2 Coating Materia
15、l 6 4.3 Application of Coating 6 4.3.1 Cleaning 6 4.3.2 Priming 6 4.3.3 Coating 6 4.4 Elbows/Bendability. 6 4.5 Workmanship and Appearance . 6 RN 1-2005 (R2013) Page ii 2013 National Electrical Manufacturers Association Foreword The purpose of this Standards Publication is to describe plastic coatin
16、gs which are applied to galvanized rigid steel conduit and galvanized steel intermediate metal conduit. This Standard covers the properties and dimensions of these coatings and is intended as an aid for selecting and obtaining the proper coating for added corrosion protection in various applications
17、 of these electrical raceways. Publication No. RN 1-2005 supersedes RN 1-1998. NEMA Standards and Authorized Engineering Information, which appears in this publication unchanged from earlier editions of this standard dating back to RN 1-1980, was reaffirmed. Metric designators and dimensions have be
18、en added. Information which has been revised is followed by the appropriate classification and the revision date. User needs have been considered in the development of this Standards Publication. This Standards Publication is reviewed periodically by the Steel Rigid Conduit and Electrical Metallic T
19、ubing Section of NEMA for changes which may be necessary to keep it up-to-date with advancing technology. Proposed or recommended revisions should be submitted to: Vice President, Technical Services National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22
20、209 This Standards Publication was developed by the NEMA Steel Rigid Conduit and Electrical Metallic Tubing Section. Section approval of the standard does not necessarily imply that all section members voted for its approval or participated in its development. At the time it was approved, the Sectio
21、n was composed of the following members: Allied Tube and Conduit CorporationHarvey, IL Beck Manufacturing, Inc. Picoma IndustriesWaynesboro, PA Maverick Tube/Republic ConduitChesterfield, MO Robroy Industries, Inc.Verona, PA Thomas & Betts CorporationMemphis, TN Western Tube and Conduit CorporationL
22、ong Beach, CA Wheatland TubeCollingswood, NJ RN 1-2005 (R2013) Page 1 2013 National Electrical Manufacturers Association Section 1 GENERAL 1.1 SCOPE These standards cover continuous polyvinyl chloride exterior coatings, corrosion resistant interior coatings, and the galvanized steel conduit, galvani
23、zed steel intermediate metal conduit, threaded couplings, and elbows to which they may be applied. 1.2 REFERENCED STANDARDS The following publications are adopted in whole or in part, as indicated by reference in this Standards Publication. American National Standards Institute (ANSI) 11 West 42nd S
24、treet New York, NY 10036 C80.1-2005 American National Standard for Rigid Steel Conduit-Zinc Coated C80.6-2005 American National Standard for Intermediate Metal Conduit American Society for Testing and Materials (ASTM) 100 Barr Harbor Drive West Conshohocken, PA 19428 D149-97a(2004) Standard Test Met
25、hods for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies This method describes a procedure for the determination of dielectric strength of solid, semi-solid, and liquid electrical insulating materials. D638-03 Standard Tes
26、t Method for Tensile Properties of Plastics This test method is used to determine the tensile strength and the percent elongation of plastic coating compounds. A Type IV specimen is tested at a crosshead speed of 2 inches (50.8 mm) per minute. D1790-02 Standard Test Method for Brittleness Temperatur
27、e of Plastic Film by Impact This method covers the determination of that temperature at which plastic film 0.25 mm (10 mils) or less in thickness exhibits a brittle failure. D2240-04 Standard Test Method for Rubber Property Durometer Hardness This method is used to determine the Shore A and Shore D
28、hardness of PVC coating compounds. G6-88(1998) Standard Test Method for Abrasion Resistance of Pipeline Coatings This method is used to determine the abrasion resistance of the applied coating material. It measures the time to loss of infinite resistance when the coating is subjected to an abrasive
29、slurry. RN 1-2005 (R2013) Page 2 2013 National Electrical Manufacturers Association G10-83(2002) Standard Test Method for Specific Bendability of Pipeline Coatings This test method is used to determine the bendability of coated conduit. It consists of bending a small-diameter specimen of coating pip
30、e around a mandrel to produce a range of short-radius bends. G153-04 Standard Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Non-metallic Materials This recommended practice covers the basic principles and standard operating procedure for light- and water-exposure apparat
31、us employing a carbon-arc light source. Underwriters Laboratories, Inc. (UL) 333 Pfingsten Road Northbrook, IL 60062 UL 6-2004 Safety Standard for Rigid Metal Conduit UL 1242-2003 Safety Standard for Intermediate Metal Conduit RN 1-2005 (R2013) Page 3 2013 National Electrical Manufacturers Associati
32、on Section 2 RIGID CONDUIT AND IMC 2.1 GALVANIZED RIGID STEEL CONDUIT Galvanized rigid steel conduit, threaded couplings, and elbows are defined in and shall conform to American National Standard C80.1, and Underwriters Laboratories Standard 6. If the threads are cut after the zinc coating has been
33、applied, the threads shall be treated with a protective coating to prevent corrosion before installing. When corrosion protection is necessary and the conduit is threaded in the field, the threads shall be coated with an approved electrically conductive, corrosion-resistant compound. Zinc-rich paint
34、 or other coatings acceptable to the Authority Having Jurisdiction (AHJ) may be used. Where unusually corrosive environments are encountered, it is recommended that threads be given additional protection suitable for the intended application. 2.2 INTERMEDIATE METAL CONDUIT Galvanized steel intermedi
35、ate metal conduit, threaded couplings, and elbows are defined in and shall conform to American National Standard C80.6 and Underwriters Laboratories Standard 1242. If the threads are cut after the zinc coating has been applied, the threads shall be treated with a protective coating to prevent corros
36、ion before installing. When corrosion protection is necessary and the conduit is threaded in the field, the threads shall be coated with an approved electrically conductive, corrosion-resistant compound. Zinc-rich paint or other coatings acceptable to the AHJ may be used. Where unusually corrosive e
37、nvironments are encountered, it is recommended that threads be given additional protection suitable for the intended application. 2.3 INTERIOR COATINGS Any supplemental interior coating shall be smooth and continuous and shall be unaffected by heat of the exterior coating process. 2.4 THREAD PROTECT
38、ORS Thread protectors shall be used on the exposed threads of the coated conduit. RN 1-2005 (R2013) Page 4 2013 National Electrical Manufacturers Association Section 3 EXTERNAL COATINGS 3.1 THICKNESS The thickness of polyvinyl chloride (PVC) coatings shall be a nominal 0.040 in. (1.02 mm). The toler
39、ance on the coating thickness shall be +0.010 in. (0.25 mm) or -0.005 in. (0.13 mm). 3.2 COATING MATERIAL The PVC coating shall have the properties specified in Table 3-1. Table 3-1 PROPERTIES OF PVC COATINGS Property Minimum Requirement ASTM Test Method Hardness: Shore A 75 D 2240 Shore D 25 D 2240
40、 Tensile Strength, psi 2000 D 638 Elongation, percent 200 D 638 Dielectric Strength, volts per mil 325 D 149 Brittleness temperature, degrees F 5 D 1790 3.3 APPLICATION OF COATING 3.3.1 Cleaning The exterior surface that is to receive the coating shall be free of grease, oil, dirt, and other extrane
41、ous matter. The surface shall be cleaned in such a manner that the galvanized surface of the conduit is not harmed or eroded. 3.3.2 Priming The cleaned exterior surface shall be primed with an adhesive suitable for use with the PVC coating material to be applied. 3.3.3 Coating The PVC material shall
42、 be applied in powder, plastisol, or pellet form by a manufacturing method which will produce a finished product conforming to these standards. 3.4 ELBOWS Coated elbows shall be used with coated conduit. The thickness of the coating on elbows shall be in accordance with Section 3.1. 3.5 COUPLINGS Co
43、ated couplings shall be used with coated conduit. The thickness of the coating on couplings shall be at least equal to the thickness of the coating on the conduit. Each coated coupling shall have a flexible PVC sleeve which extends from each end of the coupling and which will overlap the PVC coating
44、 on the conduit when the coupling has been installed on the conduit. RN 1-2005 (R2013) Page 5 2013 National Electrical Manufacturers Association The length of the sleeve extension(s) shall be at least equivalent to the nominal conduit size for sizes up through NPS 2 (53). For sizes NPS 2-1/2 (63) th
45、rough NPS 6 (155), the length of the sleeve extension(s) shall be at least 2 in. (50.8 mm). The PVC sleeve shall be a nominal thickness of 0.040 in. (1.02 mm). The inside diameter (ID) of the overlapping sleeve shall be less than the outside diameter (OD) of the PVC-coated conduit. 3.6 WORKMANSHIP A
46、ND APPEARANCE The PVC coating shall be free of blisters, bubbles, and pinholes. The PVC coating shall be continuous over the entire length of the conduit except at the threads, and shall be holiday-free at the time of manufacture. A holiday is herein defined as an electrical discontinuity of less th
47、an 80,000 ohms equivalent resistance sensed with a cellulose sponge wet with a suitable electrolyte and measured with an appropriate low-voltage direct-current instrument. A suitable electrolyte is a solution containing tap water, 3.0% salt (sodium chloride), and 0.5% liquid detergent. The inside of
48、 the PVC-coated conduit, couplings, and elbows shall be free of the PVC coating material. All sleeve extensions shall be square cut. 3.7 PERFORMANCE REQUIREMENTS Typical physical requirements for PVC-coated conduit are given in Table 3-2. Table 3-2 TYPICAL PHYSICAL PROPERTIES OF PVC-COATED RIGID CON
49、DUIT AND IMC Property Requirement* Test Method Abrasion resistance, hrs 200, no failure ASTM G6 Bendability, radius in in. at 73.4 1.8F 9 (228.6 mm) ASTM G10 Artificial weathering, hrs Minimum 1000, no adverse effect ASTM G153 *The above requirements are based on testing a 0.040 in. (1.02 mm) PVC coating applied over NPS 3/4 (21) galvanized rigid steel conduit. See Section 1 for information on the ASTM test methods. 3.8 ADHESION The adhesion of the PVC coating to the conduit shall be greater than the strength of the coating itself. This shall be determin
