1、C22.2 No. 66.3-06(reaffirmed 2011)Low Voltage Transformers Part 3: Class 2 and Class 3 TransformersUpdate No. 1C22.2 No. 66.3-06November 2012Note: For information about the Standards Update Service, go to shop.csa.ca or e-mail techsupportcsagroup.org.Title: Low Voltage Transformers Part 3: Class 2 a
2、nd Class 3 Transformers originally published April 2006The following revisions have been formally approved and are marked by a vertical line in the margin on the attached replacement pages:Revised Title page, copyright page, Contents, Preface, Clauses 1.3, 29.2, and 34.1, and Table 7New Clauses 11.6
3、 and D1.4 and Figure D1.1Deleted None Update your copy by inserting these revised pages. Keep the pages you remove for reference.CSA GroupCSA C22.2 No. 66.3-06First EditionUnderwriters Laboratories Inc.UL 5085-3First EditionLow Voltage Transformers Part 3: Class 2 and Class 3TransformersApril 17, 20
4、06(Title Page Reprinted: November 30, 2012)ANSI/UL 5085-3-2012Commitment for AmendmentsThis standard is issued jointly by the Canadian Standards Association (operating as “CSA Group”) andUnderwriters Laboratories Inc. (UL). Comments or proposals for revisions on any part of the standardmay be submit
5、ted to CSA Group or UL at any time. Revisions to this standard will be made only afterprocessing according to the standards development procedures of CSA Group and UL. CSA Group andUL will issue revisions to this standard by means of a new edition or revised or additional pages bearingtheir date of
6、issue.ISBN 1-55436-211-3 2006 CSA GroupAll rights reserved. No part of this publication may be reproduced in any form whatsoever without theprior permission of the publisher.This Standard is subject to periodic review, and suggestions for its improvement will be referred to theappropriate committee.
7、 To submit a proposal for change, please send the following information toinquirescsagroup.org and include “Proposal for change” in the subject line: Standard designation(number); relevant clause, table, and/or figure number; wording of the proposed change; and rationalefor the change.To purchase CS
8、A Group Standards and related publications, visit CSA Groups Online Store atshop.csa.ca or call toll-free 1-800-463-6727 or 416-747-4044.Copyright 2012 Underwriters Laboratories Inc.The most recent designation of ANSI/UL 5085-3 as a Reaffirmed American National Standard (ANS)occurred on November 30,
9、 2012. ANSI approval for a standard does not include the Cover Page,Transmittal Pages, Title Page (front and back), or the Preface.Comments or proposals for revisions on any part of the Standard may be submitted to UL at any time.Proposals should be submitted via a Proposal Request in ULs On-Line Co
10、llaborative StandardsDevelopment System (CSDS) at http:/.To purchase UL Standards, visit Comm 2000 at http:/m- call toll-free 1-888-853-3503.CONTENTSPreface .51 Scope .74 Construction 76 Enclosure 86.1 General .88 Connections 98.2 Wiring terminals 98.5 Leads .911 Spacings and Insulation .1011.2 Insu
11、lating material for mounting of low voltage live parts 1011.3 Coil insulation 1011.4 Insulation in lieu of spacings .10A11.5 Spacings .10A11.6 Separation of internal wiring circuits .10A12 Switches, Protective Devices, and Wiring Devices .10B12.3 Protective devices 10B12.4 Separate current-limiting
12、impedances .1212.5 Overtemperature protective devices 1217 Markings .1217.1 General .1217.3 Ratings .1217.4 Details 1318 Tests 1427 Open Circuit Secondary Voltage Test .1528 Output Current and Power Test 1628.1 Maximum current output of inherently limited transformers 1628.2 Maximum current of non-i
13、nherently limited transformers .1728.3 Maximum power of non-inherently limited transformers .1729 Calibration Test of Overcurrent Protective Devices 1930 Rated Secondary Current Test .1931 Rated Output Heating Test .1932 Dielectric Voltage-Withstand Test .2132.1 General .2132.2 Induced potential .22
14、33 Overload Heating Test 2233.1 General .2233.2 Procedure .2334 Dielectric Voltage-Withstand After Overload Heating Test 2435 Overload Test of Overcurrent or Overtemperature Protective Devices .2436 Endurance Test of Automatically Reset Overtemperature Protective Devices .2437 Strain Relief Test .25
15、Annex A (Informative)A1 Production Line Dielectric Voltage Withstand Test 31NOVEMBER 30, 2012 CSA C22.2 NO. 66.3-06 UL 5085-3 3Annex C (Informative)C1 French Translations of Markings .32Annex D (Normative)D1 Class 3 Transformers .33D1.1 General .33D1.2 Marking .33D1.3 Tests .34D1.4 Leakage current t
16、est .36NOVEMBER 30, 2012CSA C22.2 NO. 66.3-06 UL 5085-34PrefaceThis is the harmonized CSA Group and UL standard for low voltage transformers. It is the first edition ofCSA C22.2 No. 66.3 and the first edition of UL 5085-3. This harmonized standard has been jointly revisedon November 30, 2012. For th
17、is purpose, CSA Group and UL are issuing revision pages dated November30, 2012.This harmonized standard was prepared by a Technical Harmonization Committee comprised of membersfrom CSA Group, Underwriters Laboratories Inc. (UL), and representatives of the low voltage transformermanufacturing industr
18、y. The efforts and support of the members of the Technical HarmonizationCommittee are gratefully acknowledged.This Standard is considered suitable for use for conformity assessment within the stated scope of theStandard.This standard was reviewed by the CSA Subcommittee on C22.2 No. 66, under the ju
19、risdiction of the CSATechnical Committee on Industrial Products and the CSA Strategic Steering Committee on Requirementsfor Electrical Safety, and has been formally approved by the CSA Technical Committee.This Standard has been approved by the American National Standards Institute (ANSI) as an Ameri
20、canNational Standard.Where reference is made to a specific number of samples to be tested, the specified number is to beconsidered a minimum quantity.Note: Although the intended primary application of this standard is stated in its scope, it is important to note that it remainsthe responsibility of
21、the users of the standard to judge its suitability for their particular purpose.Level of harmonizationThis standard uses the IEC format but is not based on, nor is it to be considered equivalent to, an IECstandard. This standard is published as an equivalent standard for CSA Group and UL.An equivale
22、nt standard is a standard that is substantially the same in technical content, except as follows:Technical national differences are allowed for codes and governmental regulations as well as thoserecognized as being in accordance with NAFTA Article 905, for example, because of fundamental climatic,ge
23、ographical, technological, or infrastructural factors, scientific justification, or the level of protection thatthe country considers appropriate. Presentation is word for word except for editorial changes.Reasons for Differences from IECThe Technical Harmonization Committee identified the following
24、 IEC Standard within the scope of thisstandard: IEC 61558-1 (1998-07), Safety of power transformers, power supply units, and similar - Part 1:General requirements.The THC determined that the safe use of transformers and reactors is critically dependent on the electricalsystem in which they are inten
25、ded to be installed. Significant investigation is required to assess safety andsystem compatibility issues that may lead to harmonization of traditional North American transformers andreactors with those presently addressed in the known IEC standards. The THC agreed such futureinvestigation might be
26、 facilitated by completion of harmonization of North American standards fortransformers and reactors.NOVEMBER 30, 2012 CSA C22.2 NO. 66.3-06 UL 5085-3 5InterpretationsThe interpretation by the standards development organization of an identical or equivalent standard isbased on the literal text to de
27、termine compliance with the standard in accordance with the proceduralrules of the standards development organization. If more than one literal interpretation has been identified,a revision is to be proposed as soon as possible to each of the standards development organizations tomore accurately ref
28、lect the intent.CSA Group Effective DateThe effective date for CSA Group will be announced through CSA Informs or a CSA Group certificationnotice.UL Effective DateThis Standard is now in effect.PartsThe Standard for Low Voltage Transformers is divided into the following parts:Part Number Standard Ti
29、tle Standard Number1 General Requirements CSA C22.2 No. 66.1/UL 5085-12 General Purpose Transformers CSA C22.2 No. 66.2/UL 5085-23 Class 2 and Class 3 Transformers CSA C22.2 No. 66.3/UL 5085-3NOTES 1. Part 1 covers the general requirements for transformer characteristics, marking, construction, and
30、tests. Additional specificrequirements are provided in the subsequent parts.2. Part 2 and Part 3 supplement requirements and/or modify the corresponding clauses in Part 1 and should be appliedtogether with Part 1. The numbered clauses in Part 2 and Part 3 correspond to the numbered clauses in Part 1
31、.NOVEMBER 30, 2012CSA C22.2 NO. 66.3-06 UL 5085-36PART 3: CLASS 2 AND CLASS 3 TRANSFORMERS1 Scope1.1 As noted in Low Voltage Transformers Part 1: General Requirements, UL 5085-1, or CSA C22.2No. 66.1, Low Voltage Transformers Part 1: General Requirements, the requirements in Part 3 coverClass 2 tran
32、sformers for use with Class 2 circuits in accordance with the National Electrical Code,ANSI/NFPA 70, or the Canadian Electrical Code, Part I, CSA C22.1. They are intended for connection toessentially sinusoidal supply sources.Advisory Note: For transformers intended for use in the United States, the
33、se requirements also cover Class 3transformers for use with Class 3 circuits in accordance with the National Electrical Code, ANSI/NFPA 70, unlessotherwise specified in this standard. See Annex D for Class 3 requirements.1.3 In addition to the items specified in Clause 1.3 of Part 1, the requirement
34、s of Part 3 do not cover:a) Power supplies (a transformer provided with a rectifier is considered a power supply);b) Toy transformers;c) Cord and plug connected transformers other than Class 3;d) Direct plug-in transformers;e) Transformers intended for use in audio, radio, or television type applian
35、ces; orf) Other special types of transformers covered in requirements for other electrical devices orappliances.Advisory Note: The requirements of Part 3 do not cover transformers intended for use in the United States having anominal primary rating of more than 600 V and transformers having overvolt
36、age taps rated over 660 V.1.7 This part is intended to be used in conjunction with Part 1. The numbering of the clauses in Part 3corresponds to the numbered clauses in Part 1. The requirements in Part 1 apply unless modified by Part3.1.8 A Class 2 transformer that includes a separate current-limitin
37、g impedance such as a resistor or apositive temperature coefficient device (PTC) is covered by these requirements.1.9 A Class 2 transformer that includes a resonance regulating circuit is covered by these requirements.4 Construction4.2 A Class 2 transformer shall have only one secondary winding, whi
38、ch shall be insulated from theprimary winding. A winding having intermediate taps is considered a single winding.Note 1: Two or more secondary windings may be considered as a single winding and interposing insulation between thesecondary windings is not required if the windings, when interconnected,
39、 are in compliance with the performancerequirements for a single-winding construction.NOVEMBER 30, 2012 CSA C22.2 NO. 66.3-06 UL 5085-3 7Note 2: An inherently limiting type transformer marked in accordance with Clause 17.4.2 may have two secondarywindings that, when interconnected, do not comply wit
40、h the performance requirements for a single-secondary windingconstruction.Note 3: A transformer intended only for use in other equipment may have multiple secondary windings only whereisolation of all circuits can be maintained, or where the interconnection of the secondary windings is such that the
41、y complywith the performance requirements for an isolated single-secondary winding construction.4.3 There shall not be electrical connection between the primary and secondary windings of atransformer, or between a primary or secondary circuit and the enclosure.4.4 A component used to limit the outpu
42、t of a transformer to a value within the required current, power,or safety levels shall be permanent and stable in order to maintain its limiting capabilities. The followingfactors are to be considered when evaluating a limiting component:a) Effect of operating temperature;b) Electrical stress level
43、;c) Effect of transient surges; andd) Resistance to moisture.6 Enclosure6.1 General6.1.16 A transformer shall be provided with an enclosure of sheet steel, sheet aluminum, cast aluminum,cast iron, or equivalent metal, or a polymeric material. The enclosure shall contain all uninsulated liveparts and
44、 primary circuit wiring.The secondary leads or terminals of a Class 2 transformer do not have to be enclosed.The enclosure of the end product may serve as the transformer enclosure for a transformer intended foruse only in other equipment. However, the primary and secondary wiring of the transformer
45、 shall beseparated in accordance with the requirements for the end product.Note 1: For a transformer mounted on an outlet box cover or intended for mounting in a knockout of an outlet box orcabinet, the primary terminals or leads are considered enclosed by the outlet box or cabinet.Note 2: A transfo
46、rmer may have exposed primary leads if intended for connection to open wiring or concealedknob-and-tube wiring.6.1.17 The transformer shall be constructed so that it can be mounted and wired as intended in the fieldwithout exposing internal parts such as windings and protective devices to damage. Al
47、l covers, bases, andsimilar parts shall be securely fastened in place.The secondary leads or terminals of a Class 2 transformer do not have to be enclosed.The enclosure of the end product may serve as the transformer enclosure for a transformer intended foruse only in other equipment. However, the p
48、rimary and secondary wiring of the transformer shall beseparated in accordance with the requirements for the end product.APRIL 17, 2006CSA C22.2 NO. 66.3-06 UL 5085-3811.4 Insulation in lieu of spacings11.4.1 When the primary is wound with 30 AWG (0.05 mm2) or smaller wire, primary over primarycross
49、over insulation may be omitted in view of the inherent protection provided by fusing of the wire.11.5 Spacings11.5.1 At primary wiring terminals, the spacing through air or over surface between uninsulated live partsof opposite polarity, and between an uninsulated live part and a dead metal part that may be grounded,shall not be less than:a) 12.7 mm (0.5 in) when the primary voltage rating is 300 V or less andb) 25.4 mm (1 in) when the primary voltage rating exceeds 300 V.11.5.2 At points other than primary
