UL 1412-1999 UL Standard for Safety Fusing Resistors and Temperature-Limited Resistors for Radio- and Television- Type Appliances (Fifth Edition Reprint with revisions through and .pdf

1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 1412 Fusing Resistors and Temperature-Limited Resistors for Radio- and Television- Type AppliancesUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERM

2、ISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Fusing Resistors and Temperature-Limited Resistors for Radio- and Television- Type Appliances, UL 1412 Fifth Edition, Dated August 30, 1999 Summary of T

3、opics These revisions include a revised title page to reect the ANSI approval of the current edition of UL 1412. 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 vertical l

4、ine 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 new and revised requirements are substantially in accordance with Proposal(s) on this subject dated February 24, 2012. The UL Foreword i

5、s no longer located within the UL Standard. For information concerning the use and application of the requirements contained in this Standard, the current version of the UL Foreword is located on ULStandardsInfoNet at: http:/ All rights reserved. No part of this publication may be reproduced, stored

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10、andard 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 requirements that have been revised and that have a future effective date are l

11、ocated after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice. APRIL 18, 2012 UL 1412 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL APRIL 18, 2012 UL 1412 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED

12、FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL AUGUST 30, 1999 (Title Page Reprinted: April 18, 2012) 1 UL 1412 Standard for Fusing Resistors and Temperature-Limited Resistors for Radio- and Television- Type Appliances The First edition was titled Fusing Resistors and Failsafe R

13、esistors for Radio and Television Receiving Appliances and Other Electronic Equipment and numbered UL 492.2. First Edition August, 1974 Second Edition October, 1980 Third Edition July, 1988 Fourth Edition July, 1994 Fifth Edition August 30, 1999 This ANSI/UL Standard for Safety consists of the Fifth

14、 Edition including revisions through April 18, 2012. The most recent designation of ANSI/UL 1412 as an American National Standard (ANSI) occurred on April 18, 2012. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, Title Page, or effective date information. Comments or

15、 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 Collaborative Standards Development System (CSDS) at http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic c

16、opy of a Standard should be altered 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 2012 UNDERWRITERS LABORATORIES INC. ANSI/UL 1412-2012UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURT

17、HER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL APRIL 18, 2012 UL 1412 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS GENERAL 1 Scope .7 2 Glossary .7 3 References .8 CONSTRUCTION 4 General 8 5 Cor

18、rosion Protection .8 6 Insulating Material .8A 7 Spacings .9 8 Mounting .9 PERFORMANCE GENERAL 9 Arc Resistance Test 10 10 High-Current Arcing Test 10 11 Hot-Wire Ignition Test .10 12 Resistance to Moisture Test 10 13 Strain Relief Test .10 14 Torque Test 10 FUSING RESISTORS 15 Overload Test 11 16 P

19、ositive Opening Test .11 17 Opening-Time Calibration Tests 12 18 Limited Short Circuit Test 12 19 Dielectric Voltage-Withstand Test .12 TEMPERATURE-LIMITED RESISTORS 20 Representative Devices .13 21 Overload Test 13 21.1 Gradual overload test .13 21.2 Sudden overload test .13 21.3 Open resistor 17 2

20、2 Dielectric Voltage-Withstand Test .17 23 Dielectric Voltage-Withstand Test Repeated (Optional) 17 RATING 24 Details .18 APRIL 18, 2012 UL 1412 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MARKING 25 Details .18 AUGUST 30, 1999 UL 1412

21、4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL AUGUST 30, 1999 UL 1412 5 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL This page intentionally left blank. APR

22、IL 18, 2012 UL 1412 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL GENERAL 1 Scope 1.1 These requirements cover fusing resistors and temperature-limited resistors to be employed in radio- and television-type appliances. These requirements

23、also apply to resistor mounting assemblies intended for use with such resistors. The purpose of these requirements is to reduce the risk of re or electric shock by use of those resistors, but compliance of a resistor with the following requirements does not mean that it is acceptable for all applica

24、tions without evaluation in the appliance. 1.2 These requirements cover fusing resistors and temperature-limited resistors for use in radio- and television-type appliances in circuits that do not involve potentials greater than 2500 V peak. 1.3 Deleted January 21, 2004 2 Glossary 2.1 FUSING RESISTOR

25、 A resistor intended to interrupt a current ow at a predetermined time when the current passing through it exceeds a predetermined value. It is nonrenewable, (in other words it is intended to be replaced following operation). 2.2 RESISTOR MOUNTING ASSEMBLY A part that is required to secure the resis

26、tor in the appliance. It may be on, or separate from the resistor body, exclusive of pigtail leads. 2.3 TEMPERATURE-LIMITED RESISTOR A resistor whose body temperature does not exceed 600C (1112F) or ame when overload tested in accordance with Overload Test, Section 21. It is intended to provide circ

27、uit impedance and not overcurrent protection. 2.4 TRANSITION POINT The point in a line of resistors at which there is a basic construction change, such as a change in resistive element (size or material), physical size of resistor body, material, and voltage rating (see 2.5 ). 2.5 VOLTAGE RATING The

28、 voltage assigned by the manufacturer as the maximum voltage to which the resistor may be subjected that is, the voltage capability of the end-product power supply, under any fault condition, at the point where a resistor is used in a circuit. The maximum voltage shall not exceed the voltage rating

29、of the resistor. JANUARY 21, 2004 UL 1412 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 3 References Section 3 added August 30, 1999 3.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be i

30、nterpreted as referring to the latest edition of that code or standard. CONSTRUCTION 4 General 4.1 A fusing resistor shall comply with the requirements in Sections 5, 8, 15 19, 24, and 25, as applicable. 4.2 A temperature-limited resistor shall comply with the requirements in Sections 5, 8, and 20 2

31、5, as applicable. 4.3 A resistor mounting assembly shall comply with the requirements in Sections51 4a n d19.1 and 19.2. 4.4 The acceptability of a resistor covered by these requirements in any particular device or appliance depends upon its effectiveness for continued use under the conditions that

32、prevail in actual service. Accordingly, for a particular application, the resistor may be affected by the requirements for the device or appliance in question, and it may be necessary to employ protective devices having features other than or in addition to those specied in these requirements. 5 Cor

33、rosion Protection 5.1 All metal parts necessary for proper functioning of the resistor assembly shall be protected against corrosion. Exception: Parts made of nonferrous metal (properly coated or treated if necessary) do not require additional protection against corrosion. 5.2 5.1 applies to all enc

34、losing cases, and to all other parts upon which proper operation may depend. 5.3 Small, minor, noncurrent-carrying parts of iron or steel such as washers or screws need not be provided with corrosion protection unless the part ceases to perform its intended function and results in a risk of re or el

35、ectric shock. JANUARY 21, 2004 UL 1412 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6 Insulating Material 6.1 Insulating material for the support of current-carrying parts of a resistor mounting assembly shall be investigated to determin

36、e that it complies with all of the following: a) Insulating material shall have the mechanical strength needed for the application. b) Insulating material shall be classied at least V-0 as described in the Standard Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 9

37、4. c) Insulating material shall be resistant to arcing, as described in Arc Resistance Test, Section 9 and High-Current Arcing Test, Section 10. d) Insulating material shall be resistant to aming from hot-wire ignition, as described in Hot- Wire Ignition Test, Section 11. e) Insulating material shal

38、l be resistant to moisture, as described in Resistance to Moisture Test, Section 12. JANUARY 21, 2004 UL 1412 8AUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JANUARY 21, 2004 UL 1412 8B No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHO

39、RIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6.2 6.1 is intended to apply to terminal-support materials and holders of plug-in-type resistors. It is not intended to apply to coatings or enclosing cases except where employed as direct support of current-carrying parts. 7

40、Spacings 7.1 The spacings of a resistor and its mounting assembly shall not be less than those specied in Table 7.1 between any uninsulated live part and: a) Uninsulated live parts of opposite polarity, and b) Uninsulated dead metal parts. Table 7.1 Minimum acceptable spacing Potential involved in v

41、olts (RMS) Over surface, inch (mm) Through air, inch (mm) 0 125 1/16 (1.6) 1/16 (1.6) 126 250 3/34 (2.4) 3/32 (2.4) 251 600 3/16 (4.8) 5/32 (4.0) 601 2500 5/16 (7.9) 3/16 (4.8) 7.2 Uninsulated live parts, including terminals, shall be secured to their supporting surfaces by methods other than fricti

42、on between surfaces so that they are prevented from turning or shifting in position if such motion may result in reduction of spacings to less than those required elsewhere in this Standard. 8 Mounting 8.1 A resistor and its mounting assembly, when provided, shall not be adversely affected by strain

43、, pressure, or torsion on terminals or leads as determined by the tests described in Strain Relief Test, Section 13 and Torque Test, Section 14. 8.2 Bolts, screws, or other parts used for mounting a device shall be independent of those used for securing parts of the assembly. In other words, the mou

44、nting means shall not be the assembly means. AUGUST 30, 1999 UL 1412 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL PERFORMANCE GENERAL 9 Arc Resistance Test 9.1 If a material of a resistor assembly is required to be arc resistant, the mat

45、erial shall be arc resistant to the extent that tracking does not occur before 180 seconds when tested in accordance with the Standard Methods of Test for High-Voltage, Low-Current Dry Arc Resistance of Solid Electrical Insulation, ASTM D 495-89 and/or to the extent described in High-Current Arcing

46、Test, Section 10. Exception: At the manufacturers option, completed representative resistor mounting assemblies may be used instead of the rectangular specimens mentioned in 12.2. 10 High-Current Arcing Test 10.1 Each of three specimens of a material that is to be evaluated for resistance to low-vol

47、tage arcing is to be tested as described in the Standard for Polymeric Materials Short-Term Property Evaluations, UL 746A. There is to be no ignition of the representative test devices with fewer than 30 electrical arcs. 11 Hot-Wire Ignition Test 11.1 If a material of a resistor mounting assembly is

48、 required to be resistant to aming from hot-wire ignition, there shall be no ignition of any representative device within 15 seconds when the material is tested as described in the Standard for Polymeric Materials Short-Term Property Evaluations, UL 746A. 12 Resistance to Moisture Test 12.1 If a mat

49、erial of a resistor mounting assembly is required to be moisture resistant, the volume resistivity, when measured in accordance with the Standard Method of Test for D-C Resistance or Conductance of Insulating Materials, ASTM D 257-92, shall be a minimum of 10 megohm centimeters after conditioning as described in 12.2. Further, the initial (that is, before conditioning) volume resistivity shall be a minimum of 50 megohm centimeters. 12.