1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 1996 Electric Duct Heaters STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED
2、 FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Electric Duct Heaters, UL 1996 Fourth Edition, Dated August 31, 2009 SUMMARY OF TOPICS These revisions to ANSI/UL 1996 are being issued to: 1. Add safety critical functions 2. Add requirements to allow th
3、e use of UL 840 to evaluate clearance and creepage distances 3. Add requirements for electronic circuits 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 line in t
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9、chasers 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 requirements that have been
10、 revised and that have a future effective date are located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice. JULY 15, 2016 UL 1996 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JULY 15, 2016 UL 1996 tr2 No Text o
11、n This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL AUGUST 31, 2009 (Title Page Reprinted: July 15, 2016) 1 UL 1996 Standard for Electric Duct Heaters The First edition was titled the Standard for Duct Heaters. First Edition December,
12、 1992 Second Edition December, 1996 Third Edition November, 2004 Fourth Edition August 31, 2009 This ANSI/UL Standard for Safety consists of the Fourth Edition including revisions through July 15, 2016. The most recent designation of ANSI/UL 1996 as an American National Standard (ANSI) occurred on J
13、uly 14, 2016. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, Title Page, or effective date information. 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
14、-Line Collaborative Standards Development System (CSDS) at http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain
15、the sole and exclusive property of UL. COPYRIGHT 2016 UNDERWRITERS LABORATORIES INC. ANSI/UL 1996-2016UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JULY 15, 2016 ELECTRIC DUCT HEATERS - UL 1996 2 No Text on This PageUL COPYRIGHTED MATERIAL
16、 NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .6 2 General 6A 2.1 General 6A 2.2 Terminology 6A 2.3 Units of measurement .6A 2.4 Undated references .6A 2A Glossary 6A 3 Components 6B 3.1 General 6B 3.2 Attachment plugs, receptacles,
17、 connectors, and terminals 8A 3.3 Electrical enclosures and raceways 8B 3.4 Cords, cables, and internal wiring .8B 3.5 Lampholders .8C 3.6 Power supplies .8C 3.7 Printed wiring boards 8C 3.8 Controls 8D CONSTRUCTION 4 Enclosures 8F 5 Thickness of Sheet Metal Enclosures for Uninsulated Live Parts 9 6
18、 Openings in Enclosures 13 7 Enclosures, Doors, and Covers 15 8 Accessibility of Parts .16 9 Assembly .17 10 Outdoor Use Equipment .17 10.1 General .17 10.2 Enclosures 18 10.3 Field wiring connections .19 11 Mechanical Assembly .20 12 Auxiliary Devices .20 13 Connection to Power Supply .21 14 Therma
19、l Insulation and Air Filters .23 15 Terminal Parts and Leads for Field Wiring Connections .24 15.1 General .24 15.2 High-voltage circuits 25 15.3 Low-voltage circuits .28 16 Internal Wiring 29 17 Separation of Circuits .32 18 Electrical Insulation .33 19 Grounding and Bonding .34 20 Mounting of Comp
20、onents 35 21 Switches and Fan Controllers 36 22 Transformers .37 23 Electric Heaters 39 23.1 General .39 23.2 Overcurrent protection 39 23.3 Heater controls .40 JULY 15, 2016 ELECTRIC DUCT HEATERS - UL 1996 2AUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PER
21、MISSION FROM UL 24 Control Circuits .43 24A Controls .44A 24A.1 End product test parameters 44A 24A.2 Auxiliary controls 44A 24A.3 Operating controls (regulating controls) .44B 24A.4 Protective controls (limiting controls) .44C 24A.5 Controls using a temperature sensing device .44E 24B UL 60335-1 BA
22、SED REQUIREMENTS FOR THE EVALUATION OF ELECTRONIC CIRCUITS .44E 24B.1 Introduction .44E 24B.2 Construction 44G 24B.3 Performance 44J 24B.4 Manufacturing and production line testing 44Q 24B.5 Appendix .44R 25 Moisture .45 26 Spacings 45 26.1 Hazardous voltage circuits .45 26.2 Low-voltage circuits .4
23、6A 26A Clearance and Creepage Distances .46A PERFORMANCE 27 General 46A 27.1 General 46A 27.2 Supply connections .46B 27.3 Airow .46B 27.4 Inlet air 46B 27.5 Outlet air 49 27.6 Test enclosure .49 28 Temperature Tests 51 29 Power Input 54 30 Limit Control Cutout Test 55 31 Normal Tests .55 31.1 Conti
24、nuous operation .55 31.2 Nuisance tripping .56 31.3 Fan-delay control .56 32 Abnormal Tests .56 32.1 General .56 32.2 Restricted inlet .57 32.3 Fan failure .57 32.4 Blocked outlet .57 33 Backup Protection Tests .57 33.1 General .57 33.2 Restricted inlet .58 33.3 Fan failure .58 33.4 Blocked outlet .
25、58 34 Solid-State Components Test 58 35 Dielectric Voltage-Withstand Test .59 36 Insulation Resistance 59 37 Short-Circuit Tests 59 38 Overload Test High-Voltage Transformers .61 39 Burnout Test High-Voltage Transformers .61 40 Rain Test 62 JULY 15, 2016 ELECTRIC DUCT HEATERS - UL 1996 2BUL COPYRIGH
26、TED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 41 Gaskets Accelerated Aging Tests .65 MANUFACTURING AND PRODUCTION TESTS 42 Knockout Security Test 66 43 Production Line Dielectric Voltage-Withstand Tests .66 MARKING 44 General 66A 45 Equipment Marking
27、s .66A 45.1 General 66A 45.2 Determination of rating 69 46 Other Markings .69 INSTRUCTIONS 47 General 70 APPENDIX A(informative) A Example of Controls Performing as Operating or Protective Controls A1 JULY 15, 2016 ELECTRIC DUCT HEATERS - UL 1996 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER R
28、EPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements cover xed electric duct heaters, and remote control assemblies for such equipment, rated at 600 volts or less to be employed in ordinary locations in accordance with the National Electrical Code, ANSI/
29、NFPA 70. 1.2 These requirements do not cover fan-coil units, central heating furnaces, panel or cable type radiant heating equipment, electric boilers, baseboard heaters, air heaters, nor any other electric heating equipment or appliances which are covered in or as a part of separate, individual req
30、uirements. 1.3 Duct heaters intended for use in a hazardous location are judged on the basis of its compliance with the requirements in this standard, together with the requirements for hazardous location equipment included in other applicable standards. 1.4 Duct heaters designed to be connected to
31、air-duct systems are intended for installation in accordance with the Standard for the Installation of Air Conditioning and Ventilating Systems, NFPA 90A, and the Standard for the Installation of Warm Air Heating and Air Conditioning Systems, NFPA 90B. 1.5 These requirements apply to relays and othe
32、r auxiliary control devices that may be provided as part of a duct heater to make it usable with other heating or cooling equipment, and are intended to take into account the effects of operating the duct heater in conjunction with or in proximity to such equipment. 1.6 A duct heater is a self-conta
33、ined heater designed to be installed in the eld in the air stream of a ducted system, external to the air-moving unit. It is designed to be installed in a duct where an adequate ow of air from a separate, interlocked fan or blower system is provided. Such a heater may be located in the main supply d
34、uct of an air heating system, or in one of the branch ducts. Two or more duct heaters may be installed in a group (in proximity to one another in the duct) if tests indicate acceptable results when the heaters are installed in accordance with the manufacturers instructions. 1.7 A duct heater intende
35、d to be employed in conjunction with another source of heat is judged on the basis of its compliance with the requirements in this standard, and further examination and tests to determine whether or not the combination is acceptable. AUGUST 31, 2009 ELECTRIC DUCT HEATERS - UL 1996 6UL COPYRIGHTED MA
36、TERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2 General 2.1 General 2.1.1 A low voltage circuit is one that has an ac potential of not more than 30 volts alternating current (42.4 peak), and power of 100 VA or less; or 30 V dc supplied by a primary battery
37、; or supplied by a Class 2 transformer; or supplied by a combination of a transformer and xed impedance that, as a unit, complies with all the performance requirements for a Class 2 transformer. A circuit that is derived from a circuit that exceeds 30 V by connecting resistance or impedance, or both
38、, in series with the supply circuit to limit the voltage and current is not considered to be a low voltage circuit. 2.1.2 A high-voltage circuit is one having characteristics in excess of those of an low-voltage circuit. 2.1.3 Duct heaters intended for installation within 1.22 m (4 ft) of heating or
39、 cooling equipment shall be evaluated for the combination use in accordance with the requirements in the standard. See 45.1.8. 2.2 Terminology 2.2.1 Unless otherwise indicated, all voltage and current values mentioned in this standard are rms. 2.3 Units of measurement 2.3.1 Values stated without par
40、entheses are the requirement. Values in parentheses are explanatory or approximate information. 2.4 Undated references 2.4.1 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. 2A
41、 Glossary 2A added July 15, 2016 2A.1 For the purpose of this standard, the following denitions apply. 2A.2 CAPACITOR, CLASS X Capacitor or RC unit of a type suitable for use in situations where failure of the capacitor or RC unit would not lead to danger of electrical shock but could result in a ri
42、sk of re. Examples would be units connected phase to phase or phase to neutral. Notes: 1) X1 capacitors are generally used in circuits of permanently connected appliances. However, if the appliance is provided with a separate surge protective device that limits the impulse voltage to 2.5KV, an X2 ca
43、pacitor is permitted. 2) X2 capacitors are generally used in circuits of cord-connected appliances. 2A.3 CAPACITOR, CLASS Y Capacitor or RC unit of a type suitable for use in situations where failure of the capacitor could lead to danger of electric shock. Examples would be capacitors connected acro
44、ss the primary and secondary circuits where electrical isolation is required to prevent an electric shock or between hazardous live parts and accessible parts. JULY 15, 2016 ELECTRIC DUCT HEATERS - UL 1996 6AUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERM
45、ISSION FROM UL Notes: 1) Y1 capacitors are used in circuits where the prevention of electric shock is afforded solely by the isolation provided by the capacitor. Two Y2 capacitors connected in series is considered to provide the same level of protection as one Y1 capacitor. 2) Y2 capacitors are used
46、 where the prevention of electric shock is provided by the combination of the capacitor and earth ground for circuits operating at voltages 150V and 300V. 3) Y4 capacitors are used where the prevention of electric shock is provided by the combination of the capacitor and earth ground for circuits op
47、erating at voltages 150V. 2A.4 SAFETY CRITICAL FUNCTION Control, protection and monitoring functions which are being relied upon to reduce the risk of re, electric shock or casualty hazards. 3 Components 3.1 Deleted November 4, 2011 3.2 Deleted November 4, 2011 3.3 Deleted November 4, 2011 3.4 Delet
48、ed November 4, 2011 3.1 General 3.1 added November 4, 2011 3.1.1 A component of a product covered by this standard shall: a) Comply with the requirements for that component as indicated in 3.2 3.8 or the individual component section; b) Be used in accordance with its rating(s) established for the in
49、tended conditions of use; c) Be used within its established use limitations or conditions of acceptability; d) Additionally comply with the applicable requirements of this end product standard; and e) Not contain mercury. Note Specic components are incomplete in construction features or restricted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not exceeding specied limits, and shall be used only under those specic co
