1、UL 840ISBN 1-55989-391-5Insulation CoordinationIncluding Clearances andCreepage Distances forElectrical EquipmentUnderwriters Laboratories Inc. (UL)333 Pfingsten RoadNorthbrook, IL 60062-2096UL Standard for Safety for Insulation Coordination Including Clearances and Creepage Distances forElectrical
2、Equipment, UL 840Second Edition, Dated May 20, 1993Revisions: This Standard contains revisions through and including September 7, 2000.UL is in the process of converting its Standards for Safety to the Standard Generalized Markup Language(SGML), and implementing an SGML compliant document management
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7、ns dated September 7, 2000 include a reprinted title page (page1) for this Standard.The revisions dated October 6, 1999 were issued for editorial corrections. These corrections include anycombination of the following: Updated Foreword (item D); Updated Scope; title changes to UL 489 and/orUL 1950; W
8、ithdrawn standards, UL 519 and UL 547, being replaced by UL 2111; Removal of the “94”flammability classification. These revisions may also include other miscellaneous editorial corrections.As indicated on the title page (page 1), this UL Standard for Safety is an American National Standard.Attention
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13、, 2000 UL 840 tr1UL provides this Standard as is without warranty of any kind, either expressed or implied, including butnot limited to, the implied warranties of merchantability or fitness for any purpose.In no event will UL be liable for any special, incidental, consequential, indirect or similar
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24、 theaffected item. The prior text for requirements that have been revised and that have a future effective dateare located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice.New product submittals made prior to a specified future effective date will be judged under all of there
25、quirements in this Standard including those requirements with a specified future effective date, unlessthe applicant specifically requests that the product be judged under the current requirements. However, ifSEPTEMBER 7, 2000 UL 840tr2the applicant elects this option, it should be noted that compli
26、ance with all the requirements in thisStandard will be required as a condition of continued Listing and Follow-Up Services after the effectivedate, and understanding of this should be signified in writing.Copyright 2000 Underwriters Laboratories Inc.This Standard consists of pages dated as shown in
27、the following checklist:Page Date1-3.September 7, 20004 April 1, 19995.September 7, 20006-6B October 6, 19997-8ASeptember 7, 20008BOctober 6, 19999-15.May20,199316-22B .April 1, 199923.January 30, 199524 May20,199325.January 30, 199526-27May20,199328-29 January 30, 199532 .April 1, 1999SEPTEMBER 7,
28、2000 UL 840 tr3SEPTEMBER 7, 2000 UL 840tr4No Text on This PageMAY 20, 1993(Title Page Reprinted: September 7, 2000)1UL 840Standard for Insulation Coordination Including Clearances and CreepageDistances for Electrical EquipmentFirst Edition December, 1984Second EditionMay 20, 1993The most recent desi
29、gnation of UL 840 as an American National Standardoccurred on May 12, 2000.This ANSI/UL Standard for Safety, which consists of the Second edition withrevisions through September 7, 2000, is under continuous maintenance, wherebyeach revision is ANSI approved upon publication. Comments or proposals fo
30、rrevisions on any part of the Standard may be submitted to UL at any time. Writtencomments are to be sent to the UL-RTP Standards Department, 12 LaboratoryDr., Research Triangle Park, NC 27709.An effective date included as a note immediately following certain requirementsis one established by Underw
31、riters Laboratories Inc.Revisions of this Standard will be made by issuing revised 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 o
32、f revised requirements.ISBN 1-55989-391-5COPYRIGHT 1989, 2000 UNDERWRITERS LABORATORIES INC.ANSI/UL 840-2000SEPTEMBER 7, 2000UL 8402No Text on This PageCONTENTSFOREWORD 4INTRODUCTION1 Scope .52 General 62.1 Insulation coordination 62.2 Undated references .72.3 Units of measurement .82.4 Components .
33、83 Glossary .8CONSTRUCTION4 Clearance A (Equivalency) .95 Clearance B (Controlled Overvoltage) .96 Creepage Distances 117 Measurement of Clearance and Creepage Distances .167A Reserved .22A7B Use of Coatings to Achieve Insulation Coordination .22APERFORMANCE8 Switching Test .22A9 Recurring Peak Volt
34、age Determination 22B10 Dielectric Voltage-Withstand Tests .22B10.1 Testing in lieu of measuring clearances 22B10.2 Testing for controlled overvoltage 2311 Printed Wiring Board Coating Performance Test 2311.1 General .2311.2 Dielectric voltage-withstand test 2511.3 Environmental cycling test .2611.4
35、 Humidity conditioning test .2611.5 Thermal conditioning test 2611.6 Coating adhesion 2811.7 Insulation resistance between conductors .2811.8 Impulse withstand voltage .2811.9 Resistance to soldering heat .2911.10 Flammability 2911.11 Comparative tracking index (CTI) .29SEPTEMBER 7, 2000 UL 840 3FOR
36、EWORDA. This Standard contains basic requirements for products covered by Underwriters Laboratories Inc. (UL)under its Follow-Up Service for this category within the limitations given below and in the Scope sectionof this Standard. These requirements are based upon sound engineering principles, rese
37、arch, records oftests and field experience, and an appreciation of the problems of manufacture, installation, and usederived from consultation with and information obtained from manufacturers, users, inspection authorities,and others having specialized experience. They are subject to revision as fur
38、ther experience andinvestigation may show is necessary or desirable.B. The observance of the requirements of this Standard by a manufacturer is one of the conditions of thecontinued coverage of the manufacturers product.C. A product which complies with the text of this Standard will not necessarily
39、be judged to comply withthe Standard if, when examined and tested, it is found to have other features which impair the level ofsafety contemplated by these requirements.D. A product employing materials or having forms of construction which conflict with specific requirementsof the Standard cannot be
40、 judged to comply with the Standard. A product employing materials or havingforms of construction not addressed by this Standard may be examined and tested according to the intentof the requirements and, if found to meet the intent of this Standard, may be judged to comply with theStandard.E. UL, in
41、 performing its functions in accordance with its objectives, does not assume or undertake todischarge any responsibility of the manufacturer or any other party. The opinions and findings of ULrepresent its professional judgment given with due consideration to the necessary limitations of practicalop
42、eration and state of the art at the time the Standard is processed. UL shall not be responsible to anyonefor the use of or reliance upon this Standard by anyone. UL shall not incur any obligation or liability fordamages, including consequential damages, arising out of or in connection with the use,
43、interpretation of,or reliance upon this Standard.F. Many tests required by the Standards of UL are inherently hazardous and adequate safeguards forpersonnel and property shall be employed in conducting such tests.APRIL 1, 1999UL 8404INTRODUCTION1 Scope1.1 These requirements cover an alternate approa
44、ch to specifying through air and over surface spacingsfor electrical equipment through the use of the principles of insulation coordination.1.2 The complete principles of insulation coordination involve the consideration of the combination ofclearances, creepage distances, and the properties of soli
45、d insulation used to constitute the insulationsystem. The empirical data gathered thus far has been used to develop the requirements for clearancesand creepage distances as presented in this standard. The data needed to develop the evaluationprocedure for solid insulation is still being gathered. Wh
46、en available, this evaluation procedure will beadded to this standard and is not expected to affect the requirements for clearances and creepagedistances.1.3 These requirements may be used as an alternate to required spacing levels specified in end-productstandards. The end product standard spacing
47、requirements may be based on use and systems whereovervoltages are not controlled, or if controlled, the level of control is unknown.1.4 These alternate requirements are intended to be applied to a particular product category if thestandard covering the product category specifically references UL 84
48、0 or any of the requirements therein.1.5 Users of these requirements may need to specify the overvoltage levels and the methods of controlwhich will be utilized, and establish the pollution degree to which the product insulation system will beexpected to be subjected.1.6 It is not intended that the
49、test values in this standard be employed for production line testing.However, users of these requirements will need to establish a means to ensure that production controlsapplied to permit the spacing reduction remain in effect during the manufacture of the product. This couldinclude sample testing or physical measurements or another equivalent means.1.7 Users of these requirements will additionally need to ensure that influencing factors not addressed inthis standard, such as mechanical movement, field placement of conductive material, and productdamage, will no
