1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUL 2097ISBN 0-7629-1279-0Reference Standard for DoubleInsulation Systems for Use inElectronic EquipmentUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMI
2、SSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUnderwriters Laboratories Inc. (UL)333 Pfingsten RoadNorthbrook, IL 60062-2096UL Standard for Safety for Reference Standard for Double Insulation Systems for Use in ElectronicEquipme
3、nt, UL 2097Fourth Edition, Dated December 28, 2006Summary of TopicsThis new edition of UL 2097 is being issued through ULs electronic publishing system toensure format uniformity between the PDF and HTML versions of the document. Whilenumbering and figure placement, where appropriate, may have been
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19、d for their own fair and/or practical internal use.The requirements in this Standard are now in effect, except for those paragraphs, sections, tables, figures,and/or other elements of the Standard having future effective dates as indicated in the note following theaffected item. The prior text for r
20、equirements that have been revised and that have a future effective dateare located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice.New product submittals made prior to a specified future effective date will be judged under all of therequirements in this Standard including t
21、hose requirements with a specified future effective date, unlessthe applicant specifically requests that the product be judged under the current requirements. However, ifthe applicant elects this option, it should be noted that compliance with all the requirements in thisStandard will be required as
22、 a condition of continued Listing, Recognition and Follow-Up Services afterthe effective date, and understanding of this should be signified in writing.Copyright 2006 Underwriters Laboratories Inc.This Standard consists of pages dated as shown in the following checklist:Page Date1-28 .December 28, 2
23、006A1-A4December 28, 2006B1-B4December 28, 2006C1-C2 .December 28, 2006DECEMBER 28, 2006 UL 2097tr2UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 28, 20061UL 2097Reference Standard for Double Insulation Systems for Use in ElectronicE
24、quipmentFirst Edition June, 1990Second Edition May, 1994Third Edition February, 1999Fourth EditionDecember 28, 2006An effective date included as a note immediately following certain requirementsis one established by Underwriters Laboratories Inc.Revisions of this Standard will be made by issuing rev
25、ised or additional pagesbearing their date of issue. A UL Standard is current only if it incorporates themost recently adopted revisions, all of which are itemized on the transmittal noticethat accompanies the latest set of revised requirements. Comments or proposalsfor revisions on any part of the
26、Standard may be submitted to UL at any time.Proposals should be submitted via a Proposal Request in ULs On-LineCollaborative Standards Development System (CSDS) at http:/.ISBN 0-7629-1279-0COPYRIGHT 2006 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR
27、DISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 28, 2006UL 20972No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTS1 Introduction 41.1 Scope .41.2 General .51.3 Glossary 51.4 General requirements .81.5 General conditio
28、ns for tests .111.6 Markings .122 Fundamental Construction Requirements .132.1 Protection against electric shock 132.2 Insulation .142.3 SELV circuits and dead metal parts 172.4 Spacings (creepage distances and clearances) .182.5 Safety isolating transformers 193 Supply 203.1 Insulation .203.2 Power
29、 supply cords 204 Physical Requirements .204.1 General 205 Thermal and Electrical Requirements .215.1 Leakage current test .215.2 Dielectric voltage-withstand tests 245.3 Overload conditioning on safety isolating transformer insulation .25APPENDIX A Guidelines and Applications for Double Insulation
30、Systems for Electronic EquipmentAPPENDIX B Insulation Typically Required Between Parts of EquipmentAPPENDIX C International Electrical SymbolDECEMBER 28, 2006 UL 2097 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL1 Introduction1.1 Scope1.1.
31、1 These requirements cover double insulation systems intended for use in ungrounded electronicequipment marked Double Insulation,Double Insulated, or with the double-insulation symbol intendedto be employed in accordance with the National Electrical Code, ANSI/NFPA 70.1.1.2 These requirements also c
32、over:a) Equipment required by the end-product standard to be provided with a double insulationsystem and to be grounded andb) Double-insulated equipment permitted by the end-product standard to be provided with anon-functional means for grounding.1.1.3 Equipment marked Double Insulation,Double Insul
33、ated, or with the double-insulation symbolshall comply with the applicable requirements in this standard and in the standard covering the particulartype of equipment the end-product standard. In cases where the end-product standard containsrequirements for double insulation, the end-product standard
34、 takes precedence. It is intended that therequirements in this standard be applied to end products marked as described unless the end-productstandard specifies different requirements.1.1.4 These requirements were developed for categories that do not have double insulation requirements,to provide gui
35、dance about double insulation systems, and to promote consistent approaches to doubleinsulation. Double insulation requirements for electronic equipment are applicable to the double insulationsystems used in products contained in various end-product, component and systems standards.Guidelines and Ap
36、plications for Double Insulation Systems for Electronic Equipment in Appendix Acovers:a) Level of Protection Provided by Double Insulation,b) Methods to Address Product-Specific Double Insulation Requirements, andc) Guidelines for Including Double Insulation Requirements in an End-Product Standard.1
37、.1.5 A product that contains features, characteristics, components, materials, or systems new or differentfrom those covered by the requirements in this standard, and that involves a risk of fire, electric shock, orinjury to persons shall be evaluated using the appropriate additional component and e
38、nd-productrequirements to determine that the level of safety as originally anticipated by the intent of this standard ismaintained. A product whose features, characteristics, components, materials, or systems conflict withspecific requirements or provisions of this standard shall not be judged to co
39、mply with this standard.Where appropriate, revision of requirements shall be proposed and adopted in conformance with themethods employed for development, revision, and implementation of this standard.DECEMBER 28, 2006UL 20974UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBU
40、TION WITHOUT PERMISSION FROM UL1.2 General1.2.1 Units of measurement1.2.1.1 If a value for measurement is followed by a value in other units in parentheses, the second valuemay be only approximate. The first stated value is the requirement.1.2.1.2 Unless otherwise indicated, all voltage and current
41、values mentioned in this standard areroot-mean-square (rms).1.2.2 Undated references1.2.2.1 Any undated reference to a code or standard appearing in the requirements of this standard shallbe interpreted as referring to the latest edition of that code or standard.1.3 Glossary1.3.1 For the purpose of
42、this standard the following definitions apply.1.3.2 ACCESSIBLE PART OR SURFACE A part or surface subject to contact by persons under anycondition of user operation or user function, including user (or operator)In a determination of whether a part or surface is accessible to such contact, the criteri
43、a specified in the end-product standard areto be applied.1.3.3 BARRIER A part providing protection against direct contact.1.3.4 BASIC INSULATION The insulation necessary to provide basic protection against the risk ofelectric shock.1.3.5 DEAD METAL PART A metal or other electrically conductive part,
44、 accessible or inaccessible,that is not a live part.1.3.6 DOUBLE INSULATION An insulation system comprised of both basic insulation andsupplementary insulation.1.3.7 ELV (EXTRA-LOW VOLTAGE) CIRCUIT A circuit that is constructed and protected so that thevoltage between conductors or between a conduct
45、or and earth ground does not exceed the limits forrisk of electric shock as identified in the end-product standard and that is separated from higher voltagecircuits by at least basic insulation, but that does not meet the requirements for an SELV circuit.For the purposes of these requirements, an EL
46、V circuit may be considered an inaccessible dead metal part.1.3.8 INSULATION WORKING VOLTAGE The highest steady-state voltage (transients, includingswitching transients, are to be disregarded) to which the insulation under consideration is, or can be,subjected under intended operating conditions.The
47、 method for determining the insulation working voltage is described in 2.2.1.5.1.3.9 LIVE PART A part that is conductively connected to a circuit that operates at a voltage thatexceeds the limits for risk of electric shock as identified in the end-product standard with reference toground or accessib
48、le metal, and in which the available current measured exceeds the current value foraccessible parts specified in the end-product standard.DECEMBER 28, 2006 UL 2097 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL1.3.10 OPERATIONAL INSULATION
49、Insulation that is necessary for the correct operation of theequipment but that is not relied upon for protection against electric shock.For the purposes of these requirements, parts insulated by operational insulation only are considered to be uninsulated. Forexample, parts in ELV circuits and live parts, protected only by lacquer, enamel, ordinary paper, cotton, oxide film, beads, or sealingcompounds other than self-hardening resin are considered to be uninsulated parts.
