UL 746C-2018 UL Standard for Safety Polymeric Materials C Use in Electrical Equipment Evaluations (Seventh Edition).pdf

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1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 746C Polymeric Materials Use in Electrical Equipment Evaluations STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL

2、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Polymeric Materials Use in Electrical Equipment Evaluations, UL 746C Seventh Edition, Dated February 5, 2018 SUMMARY OF TOPICS This New Edition of ANSI/UL 746C includ

3、es the Alignment of the Text in Paragraph 9.4 with that of Table 6.1 for the Comparative Tracking Index (CTI) Test The new requirements are substantially in accordance with Proposal(s) on this subject dated September 29, 2017 and December 1, 2017. All rights reserved. No part of this publication may

4、 be reproduced, stored in a retrieval system, or transmitted in any form by any means, electronic, mechanical photocopying, recording, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to,

5、 the implied warranties of merchantability or tness for any purpose. In no event will UL be liable for any special, incidental, consequential, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising out of the use of or the inability to use this

6、 Standard, even if UL or an authorized UL representative has been advised of the possibility of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety

7、agree to defend, indemnify, and hold UL harmless from and against any loss, expense, liability, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. FEBRU

8、ARY 5, 2018 UL 746C tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL FEBRUARY 5, 2018 UL 746C tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL FEBRUARY 5, 20

9、18 1 UL 746C Standard for Polymeric Materials Use in Electrical Equipment Evaluations The rst edition was titled Test for Polymeric Enclosures of Portable Electrical Appliances and numbered UL 746.51. First Edition June, 1973 Second Edition March, 1978 Third Edition May, 1989 Fourth Edition December

10、, 1995 Fifth Edition November, 2001 Sixth Edition September, 2004 Seventh Edition February 5, 2018 This ANSI/UL Standard for Safety consists of the Seventh Edition. The most recent designation of ANSI/UL 746C as an American National Standard (ANSI) occurred on February 5, 2018. ANSI approval for a s

11、tandard does not include the Cover Page, Transmittal Pages, and Title Page. The Department of Defense (DoD) has adopted UL 746C on November 3, 1998. The publication of revised pages or a new edition of this Standard will not invalidate the DoD adoption. Comments or proposals for revisions on any par

12、t of the Standard may be submitted to UL at any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at https:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altere

13、d in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2018 UNDERWRITERS LABORATORIES INC. ANSI/UL 746C-2018UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION W

14、ITHOUT PERMISSION FROM UL FEBRUARY 5, 2018 UL 746C 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .7 2 General 7 3 Glossary .9 ENCLOSURES 4 General .13 5 Portable Unattended Household Equi

15、pment Alternate Path 15 5.1 General 15 5.2 Electrical connections 16 5.3 Materials adjacent to connections .16 5.4 Wire, tubing, sleeving and tape .17 ELECTRICAL INSULATION 6 Material Property Considerations 17 6.1 General 17 6.2 Evaluation of materials not meeting preselection test performance leve

16、ls in Table 6.1 .23 7 Internal Barriers .24 PERFORMANCE CRITERIA 8 General .24 ELECTRICAL 9 Comparative Tracking Index (CTI) .25 10 Dielectric Strength 26 11 High Current Arc Resistance to Ignition (HAI) 26 12 Hot-Wire Ignition (HWI) Abnormal Overload Test or Glow-Wire End-Product Test .27 12.1 Gene

17、ral .27 12.2 Abnormal overload test .27 12.3 Glow-wire end-product test (GWEPT) .28 13 Inclined Plane Tracking 28 14 Volume Resistivity 28 FLAMMABILITY 15 Flammability 12 mm Flame .29 16 Flammability 20 mm (3/4-Inch) Flame .29 17 Flammability 127 mm (5 Inch) Flame 29 18 Enclosure Flammability 746-5V

18、S 30 18.1 Test criteria 30 19 Enclosure Flammability Large Surface Area Considerations 30 20 Flame-Retardant Coatings .31 20.1 General .31 20.2 Test criteria 32 FEBRUARY 5, 2018 UL 746C 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MECHAN

19、ICAL 21 Crushing Resistance 32 22 Resistance to Impact 32 DIMENSIONAL CHANGE OF POLYMERIC PARTS 23 Creep .33 PERMANENCE 24 Permanence .34 24.1 General .34 24.2 Vicat softening point 34 24.3 Heat deection temperature .34 24.4 Ball pressure temperature .34 25 Ultraviolet Light Exposure 34 26 Water Exp

20、osure and Immersion 35 26.1 General .35 26.2 Dimensional change 36 SPECIAL END-USE CONSIDERATIONS 27 Abnormal Operation .36 28 Severe Conditions 36 THERMAL 29 Mold Stress-Relief Distortion .36 30 Input to Motor 37 31 Strain-Relief Test after Mold Stress-Relief Distortion 37 32 Temperature Considerat

21、ions General 37 33 Functional-Use Temperature Indices 38 34 Generic Thermal Indices .40 35 Relative Thermal Index 40 36 Relative Thermal Capability 41 37 Relative Thermal Capability (Alternate) 42 38 Temperature Excursions Beyond the Maximum Use Temperature 45 SPECIALIZED APPLICATIONS 39 General Adh

22、esives 46 40 Function Analysis .46 41 Program of Investigation 47 41.1 End-product evaluation .47 41.2 Effect of environmental conditions 47 42 Coil Forms .47 43 Conformal Coatings .47 METALLIZED PARTS 44 General 47 45 Ductile Coatings 48 FEBRUARY 5, 2018 UL 746C 4UL COPYRIGHTED MATERIAL NOT AUTHORI

23、ZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 46 Brittle Coatings .48 TEST PERFORMANCE 47 General 49 47.1 Details 49 47.2 Voltmeters .49 47.3 Cheesecloth indicators 49 47.4 Supply-circuit voltage and frequency 49 48 End-Product Arc Resistance Test .50 49 Abnormal Overload T

24、est .50 50 Flammability 12 mm Flame Test 52 51 Flammability 20 mm (3/4 Inch) Flame Test .53 52 Flammability 127 mm (5 inch) Flame Test .55 53 Enclosure Flammability 746-5VS Test .56 53.1 Apparatus .56 53.2 Plaque conditioning .57 54 Flame-Retardant Coatings Test .59 54.1 Specimen conditioning 59 54.

25、2 Test methods 60 54.3 Other considerations 61 55 Crushing Resistance Test 61 56 Resistance to Impact Test .62 57 Ultraviolet Light Exposure Test .66 57.1 Apparatus .66 57.2 Method .66 58 Water Exposure and Immersion Test 72 59 Abnormal Operation Test 73 60 Severe Conditions Test 74 61 Mold Stress-R

26、elief Distortion Test .74 62 Ball Pressure Test on End-Product .75 63 Input to Motors Test .75 64 Relative Thermal Capability 75 65 Relative Thermal Capability (Alternate) 76 66 Temperature Excursions Beyond the Maximum Use Temperature 77 67 Temperature Considerations Illustrative Example .79 68 Tem

27、perature Considerations Illustrative Example (Alternate RTC) .81 69 Adhesives Specialized Applications .84 69.1 General .84 69.2 As-received test 84 69.3 Effect of temperature .84 69.4 Effect of humidity .86 69.5 Effect of cold 86 69.6 Effect of cyclic conditions 86 69.7 Other test considerations 87

28、 COIL FORMS 70 Conformal Coating Test .87 71 Tape Adhesion Test .87 71.1 General .87 71.2 Samples 88 71.3 Coating thickness measurement .88 FEBRUARY 5, 2018 UL 746C 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 71.4 Sample preparation .88

29、 71.5 Conditioning .89 71.6 Results .89 72 Leakage Current Test .90 73 Glow-Wire End-Product Test .92 73.1 General .92 73.2 Signicance .92 MARKING 74 General 93 APPENDIX A Guidelines for Evaluation of Substitute Polymeric Materials A1 Alternate Enclosure Material Considerations .A1 FEBRUARY 5, 2018

30、UL 746C 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements cover parts made of polymeric materials that are used in electrical equipment and describe the various test procedures and their use in the

31、testing of such parts and equipment. 1.2 These requirements do not cover the specic insulating systems that are covered by the requirements contained in the Standard for Systems of Insulating Materials General, UL 1446. 1.3 Test procedures are provided herein for the evaluation of polymeric material

32、s in specic applications. These test procedures include references to data obtained from small-scale property tests conducted under standard conditions as well as other practical means of evaluation. 1.4 Unless otherwise indicated, parts made by Additive-Manufacturing (AM) Technology shall be evalua

33、ted by subjecting the end-product part or test specimens cut from the end-product part to the specied test. For preselection purposes, test specimens printed in the specied dimensions or cut to the specied dimensions from a printed part may represent the end product when the same production conditio

34、ns are used. 2 General 2.1 If a value for measurement is followed by a value in other units, the use of either value can be expected to provide equivalent results in the application of such requirements. Each of the requirements is stated in SI units as well as in U.S. customary units. Equivalent, a

35、lthough not necessarily exactly identical results, are to be expected from applying a requirement in SI units or U.S. customary units. Equipment calibrated in metric units is to be used when a requirement is applied in metric terms. 2.2 Any undated reference to a code or standard appearing in the re

36、quirements of this standard shall be interpreted as referring to the latest edition of that code or standard. 2.3 For reference purposes, Figure 2.1 describes the procedure to be followed in the evaluation of parts made of polymeric materials and covered by the requirements in this standard. This is

37、 generated text for gtxt. FEBRUARY 5, 2018 UL 746C 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL Figure 2.1 UL 746C guide for polymeric evaluations FEBRUARY 5, 2018 UL 746C 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION

38、OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.4 The Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94, covers ammability of polymeric materials used for parts in devices and appliances. The Standard for Polymeric Materials Short Term Property Evaluati

39、ons, UL 746A, contains short-term test procedures to be used for the evaluation of materials used for parts intended for specic applications in electrical end- products. The Standard for Polymeric Materials Long Term Property Evaluations, UL 746B, contains long-term test procedures to be used for th

40、e evaluation of materials used for parts intended for specic applications in end-products. The Standard for Polymeric Materials Fabricated Parts, UL 746D, contains requirements for traceability and performance of parts molded and fabricated from polymeric materials. 2.5 Requirements for materials th

41、at have been modied to match the requirements of a specic application, including the use of recycled and regrind materials, the use of additives and colorants, and the blending of two or more materials, are described in the Standard for Polymeric Materials Fabricated Parts, UL 746D. 3 Glossary 3.1 F

42、or the purposes of this standard the following denitions apply: 3.2 ACCESSIBLE PART A part so located that it can be contacted by a person, either directly or by means of a probe or a tool, or that is not recessed the required distance behind an opening. 3.3 ATTENDED EQUIPMENT Equipment intended for

43、 use where operator presence is required for the equipment to function but is not necessarily required for the equipment to operate. Operator absence is effectively limited to short durations due to one or more characteristics of the equipment such as production of excessive noise or vibration. Exam

44、ples may include hand-held drills, electric knives, can openers, hand-held hair dryers, blenders, and vacuum cleaners. 3.4 BRANCH CIRCUIT A branch circuit is that portion of the building wiring system beyond the nal overcurrent device on the power- distribution panel protecting the circuit to the el

45、d-wiring terminals of permanently connected equipment or to the receptacle outlet for cord-connected appliances. 3.5 COMPARATIVE TRACKING INDEX Comparative tracking index (CTI) is determined by the method described in the Standard for Polymeric Materials Short Term Property Evaluations, UL 746A, Rec

46、ommended Method for Determining the Comparative Tracking Index of Solid Insulating Materials Under Moist Conditions. FEBRUARY 5, 2018 UL 746C 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CTI range tracking index Assigned PLC (Volts) 600

47、TI 0 400 TI 600 1 250 TI 400 2 175 TI 250 3 100 TI 175 4 0 TI 100 5 3.6 CONFORMAL COATING A protective covering applied on a printed wiring board to increase the dielectric voltage-withstand capability between conductors and to protect against environmental conditions. 3.7 CORD-CONNECTED UNIT An app

48、liance or product intended for connection to the branch-circuit power line by means of a power supply cord. 3.8 COUNTER-SUPPORTED APPLIANCE An appliance that is physically supported by a counter, table or bench during the performance of its intended function. 3.9 DECORATIVE PART A part used for orna

49、mental purposes only and not as an enclosure or insulation of electrically live parts. 3.10 ENCLOSURE That part of the product that: a) Renders inaccessible all or any parts of the equipment that may otherwise present a risk of electric shock and/or b) Retards propagation of ame initiated by electrical disturbances occurring within. 3.11 FIELD-WIRING TERMINAL Any terminal where a power supply or other wire can be connected by