UL 840-2005 UL Standard for Safety Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipment (Third Edition Reprint with Revisions Through and In.pdf

1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 840 Insulation Coordination Including Clearances and Creepage Distances for Electrical EquipmentUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMIS

2、SION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipment, UL 840 Third Edition, Dated January 6, 2005 Summary of Topic

3、s This revision to ANSI/UL 840 includes revised requirements for: Surge Protective Devices Used in Electrical Equipment Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. Changes in requirements are marked with a ver

4、tical line in the margin and are followed by an effective date note indicating the date of publication or the date on which the changed requirement becomes effective. The revised requirements are substantially in accordance with Proposal(s) on this subject dated August 12, 2011 and October 21, 2011.

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9、nic Standard on the purchasers computer system. The requirements in this Standard are now in effect, except for those paragraphs, sections, tables, gures, and/or other elements of the Standard having future effective dates as indicated in the note following the affected item. The prior text for requ

10、irements that have been revised and that have a future effective date are located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice. MAY 4, 2012 UL 840 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 4, 2012 UL

11、840 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JANUARY 6, 2005 (Title Page Reprinted: May 4, 2012) 1 UL 840 Standard for Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipmen

12、t First Edition December, 1984 Second Edition May, 1993 Third Edition January 6, 2005 This ANSI/UL Standard for Safety consists of the Third Edition including revisions through May 4, 2012. The most recent designation of ANSI/UL 840 as an American National Standard (ANSI) occurred on May 3, 2012. AN

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15、lusive property of UL. COPYRIGHT 2012 UNDERWRITERS LABORATORIES INC. ANSI/UL 840-2012UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MAY 4, 2012 UL 840 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR

16、DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .4 2 Glossary .5 3 Units of Measurement 6A 4 Undated References .6A 5 Components 6A 6 Insulation Coordination 7 CONSTRUCTION 7 Clearance A (Equivalency) .9 8 Clearance B (Controlled Overvoltage) 10 9 Creepage Distances 12 10 Measu

17、rement of Clearance and Creepage Distances .15 11 Use of Coatings to Achieve Insulation Coordination .23 PERFORMANCE 12 Switching Test 23 13 Recurring Peak Voltage Determination 23 14 Dielectric Voltage-Withstand Tests 24 14.1 Testing in lieu of measuring clearances .24 14.2 Testing for controlled o

18、vervoltage 25 15 Printed Wiring Board Coating Performance Test 25 15.1 General .25 15.2 Dielectric voltage-withstand test 27 15.3 Environmental cycling test .28 15.4 Humidity conditioning test .28 15.5 Thermal conditioning test 28 15.6 Coating adhesion 30 15.7 Insulation resistance between conductor

19、s .30 15.8 Impulse withstand voltage .31 15.9 Resistance to soldering heat .31 15.10 Flammability 31 15.11 Comparative tracking index (CTI) .31 MAY 4, 2012 UL 840 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 Thes

20、e requirements cover an alternate approach to specifying through air and over surface spacings for 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 of clearances, cre

21、epage distances, and the properties of solid insulation used to constitute the insulation system. The empirical data gathered thus far has been used to develop the requirements for clearances and creepage distances as presented in this standard. The data needed to develop the evaluation procedure fo

22、r solid insulation is still being gathered. When available, this evaluation procedure will be added to this standard and is not expected to affect the requirements for clearances and creepage distances. 1.3 These requirements may be used as an alternate to required spacing levels specied in end-prod

23、uct standards. The end product standard spacing requirements may be based on use and systems where overvoltages 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 the standard covering

24、 the product category specically references UL 840 or any of the requirements therein. 1.5 Users of these requirements may need to specify the overvoltage levels and the methods of control which will be utilized, and establish the pollution degree to which the product insulation system will be expec

25、ted to be subjected. 1.6 It is not intended that the 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 controls applied to permit the spacing reduction remain in effect during the manufa

26、cture of the product. This could include sample testing or physical measurements or another equivalent means. 1.7 Users of these requirements will additionally need to ensure that inuencing factors not addressed in this standard, such as mechanical movement, eld placement of conductive material, and

27、 product damage, will not affect the system for insulation coordination. Examples are the deformation of the enclosure, movement of the ttings for conduit or armored cable, or the improper installation of eld wiring. Clearances and creepage distances at those locations must be veried for compliance

28、by physical measurement in accordance with Section 10, Measurement of Clearance and Creepage Distances. JANUARY 6, 2005 UL 840 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2 Glossary 2.1 For the purpose of this standard, the following de

29、nitions apply. 2.2 CLEARANCES Through air spacing. 2.2A COMBINATION WAVEFORM A surge delivered by a generator which has the inherent capability of applying a 1.2/50 s voltage wave across an open circuit, and delivering an 8/20 s current wave into a short circuit. Also called a combination surge. 2.2

30、A added May 4, 2012 2.3 CREEPAGE DISTANCES (CREEPAGES) Over surface spacings. 2.4 FUNCTIONAL OVERVOLTAGE Deliberately imposed transient overvoltages necessary for the function of a device. 2.5 GENERAL ENVIRONMENT The overall area or space in which the equipment is located. Commonly referred to as am

31、bient conditions. 2.6 IMPULSE WITHSTAND VOLTAGE The highest peak value of impulse voltages, of prescribed form and polarity, that does not cause breakdown under specied conditions of test. 2.7 INSULATION COORDINATION The correlation of insulating characteristics of electrical equipment: a) With expe

32、cted overvoltages and characteristics of overvoltage protective devices (a key consideration for clearances); and b) With the expected micro-environment and pollution protective means (key considerations for creepage distances). 2.8 LEAKAGE CURRENT The current that can be measured as owing between t

33、est points during a dielectric voltage-withstand test. 2.9 LIGHTNING OVERVOLTAGE The transient overvoltage at a given location on a system due to a specic lightning discharge. 2.10 MICRO-ENVIRONMENT The conditions that immediately surround the clearance or creepage distance under consideration. The

34、micro-environment of the creepage distance or clearance and not the general environment of the equipment determines the effect on the insulation. The micro-environment might be less severe or more severe than the general environment that the equipment is in. It includes all factors inuencing the ins

35、ulation, such as climatic, electromagnetic, and generation of pollution. 2.10A NOMINAL DISCHARGE CURRENT (In) Peak value of the current, selected by the manufacturer, through the SPD having a current waveshape of 8/20 where the SPD remains functional after 15 surges. 2.10A added May 4, 2012 2.11 OPE

36、RATING VOLTAGE The voltage across two points occurring due to normal operation of the product when controls are set in any position. MAY 4, 2012 UL 840 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.12 OVERVOLTAGE CATEGORY Grouping of pr

37、oducts based on typical installed location with respect to overvoltage protection and available energy. See note c of Table 8.1. 2.13 POLLUTION Any addition of contaminants, solid, liquid or gaseous (ionized gases), and moisture that may produce a reduction of dielectric strength or surface resistiv

38、ity. 2.14 POLLUTION DEGREE The level of pollution present at the location on or in a product where the clearance and creepage distance measurement is made, and can be controlled by design of the product. For example, enclosures can be used to achieve pollution degree 3, heaters within enclosures can

39、 help achieve pollution degree 2, and encapsulation can be used to achieve pollution degree 1. See 9.3. 2.15 RATED VOLTAGE The voltage employed for test purposes by the end-product standard. 2.16 RECURRING PEAK VOLTAGE Deliberately or naturally imposed transient overvoltage that exceeds the steady s

40、tate voltage, and is caused by operating a control or adjustable component. The voltage level will be consistent for the same operation under the same conditions. Insulating materials can be degraded by ozone generated by partial discharges due to recurring peak voltages. 2.16A SURGE PROTECTIVE DEVI

41、CE (SPD) TYPE DESIGNATIONS SPD Type designations are as follows: TYPE 1 Permanently connected SPDs intended for installation between the secondary of the service transformer and the line side of the service equipment overcurrent device, as well as the load side, including watt-hour meter socket encl

42、osures and intended to be installed without an external overcurrent protective device. TYPE 2 Permanently connected SPDs intended for installation on the load side of the service equipment overcurrent device - including SPDs located at the branch panel. TYPE 3 Point of utilization SPDs, installed at

43、 a minimum conductor length of 10 meters (30 feet) from the electrical service panel to the point of utilization, for example cord connected, direct plug-in, receptacle type and SPDs installed at the utilization equipment being protected. The distance of 10 meters (30 feet) is exclusive of conductor

44、s provided with or used to attach SPDs. TYPE 4 COMPONENT ASSEMBLIES Component assembly consisting of one or more Type 5 components together with a disconnect (integral or external) or a means of complying with the limited current tests. TYPE 1, 2, 3 COMPONENT ASSEMBLIES Consists of a Type 4 componen

45、t assembly with internal or external short circuit protection. TYPE 5 Discrete component surge suppressors, such as MOVs that may be mounted on a PWB, connected by its leads or provided within an enclosure with mounting means and wiring terminations. 2.16A added May 4, 2012 2.17 SWITCHING OVERVOLTAG

46、E The transient overvoltage at a given location on a system due to a specic switching operation or fault. 2.18 SYSTEM VOLTAGE The rated supply or line voltage to which the product will be connected. MAY 4, 2012 UL 840 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION W

47、ITHOUT PERMISSION FROM UL 2.19 TRANSIENT OVERVOLTAGE Nonperiodic voltages that may be caused by switching, lightning, or function of a device. 3 Units of Measurement 3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information. 4 Undated

48、 References 4.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or standard. 5 Components 5.1 Except as indicated in 5.2, a component of a product covered by this standard shall comply wit

49、h the requirements for that component. 5.2 A component is not required to comply with a specic requirement that: a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard, or b) Is superseded by a requirement in this standard. 5.3 A component shall be used in accordance with its rating established for the intended conditions of use. 5.4 Specic components are incomplete in construction features