1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 497B Protectors for Data Communications and Fire-Alarm CircuitsUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERI
2、AL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Protectors for Data Communications and Fire-Alarm Circuits, UL 497B Fourth Edition, Dated June 14, 2004 Summary of Topics This revision of ANSI/UL 497B is being issued to reaffirm ANSI ap
3、proval of the Standard. 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 the margin and are followed by an effective date note indicating the date of publi
4、cation or the date on which the changed requirement becomes effective. The revisions are substantially in accordance with Proposal(s) on this subject dated October 26, 2012 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form by
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9、, 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 located after the Standard, and are preceded by a SUPE
10、RSEDED REQUIREMENTS notice. DECEMBER 17, 2012 UL 497B tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL DECEMBER 17, 2012 UL 497B tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOU
11、T PERMISSION FROM UL JUNE 14, 2004 (Title Page Reprinted: December 17, 2012) 1 UL 497B Standard for Protectors for Data Communications and Fire-Alarm Circuits Prior to the rst edition, the requirements for the products covered by this standard were included in the Standard for Protectors for Communi
12、cations Circuits, UL 497. First Edition January, 1987 Second Edition December, 1993 Third Edition February, 1999 Fourth Edition June 14, 2004 This ANSI/UL Standard for Safety consists of the Fourth Edition including revisions through December 17, 2012. The most recent designation of ANSI/UL 497B as
13、a Reaffirmed American National Standard (ANS) occurred on December 17, 2012. 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.
14、 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 copy of a Standard should be altered in any way. All of ULs Standards and all copyrights,
15、 ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2012 UNDERWRITERS LABORATORIES INC. ANSI/UL 497B-2004 (R2012)UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL DECEMBER 17, 2012 UL
16、 497B 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .5 2 General 5 2.1 Components .5 2.2 Units of measurement .6 2.3 Undated references .6 3 Glossary .6 CONSTRUCTION 4 General 7 5 Enclosu
17、res .7 5.1 General .7 5.2 Sheet metal 7 5.3 Nonmetallic 8 6 Corrosion Protection .10 7 Field-Wiring Connections .10 7.1 General 10 7.2 Field-wiring terminals 10 7.3 Applique units 11 8 Components 11 8.1 General 11 8.2 Arrester assemblies 12 8.3 Electrical insulation material 12 9 Spacings 12 10 Fuse
18、s .13 PERFORMANCE 11 General 13 12 Strike Voltage Breakdown Test .15 13 Endurance Conditioning .15 14 Temperature Test .15 15 Variable Ambient Conditioning 16 16 Humidity Conditioning .16 17 Dielectric Voltage-Withstand Test .16 18 Vibration Conditioning .17 19 Jarring Test 17 20 High Temperature Te
19、st 18 21 Discharge Test .19 22 Repeated Discharge Test 19 23 Polymeric Materials Tests 20 23.1 General .20 23.2 Distortion 20 23.3 Flame .20 24 Lead Strain-Relief Test 21 JUNE 14, 2004 UL 497B 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL
20、 MARKING 25 General 21 JUNE 14, 2004 UL 497B 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements cover protectors for data communications and re-alarm circuits. 1.2 As covered by these requirements, d
21、ata communications circuit protectors and re-alarm circuit protectors consist of single- and multiple-pair air-gap arresters, gas-tube arresters, or solid-state arresters, with or without fuses or other voltage-limiting devices. Data communications circuit protectors and re-alarm circuit protectors
22、are intended to protect equipment, wiring, and personnel against the effects of excessive potentials and currents caused by lightning in communications alarm-initiating or alarm-indicating loop circuits. 1.3 This standard does not cover the following: a) Lightning protective devices for the protecti
23、on of primary distribution wiring systems and equipment such as AC branch circuit protection. b) Antenna discharge units for radio- and television-receiving appliances. c) Lightning conductor and air terminals for connection of lightning rods for building protection. d) Protective devices to be used
24、 on telephone lines or telephone lines connecting to the telecommunication networks. 1.4 A product that contains features, characteristics, components, materials, or systems new or different from those in use when the standard was developed, and that involves a risk of re, electric shock, or injury
25、to persons shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the level of safety for the user of the product as originally anticipated by the intent of this Standard. 2 General 2.1 Components 2.1.1 Except as indicated in 2.
26、1.2, a component of a product covered by this standard shall comply with the requirements for that component. 2.1.2 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
27、 this standard, or b) Is superseded by a requirement in this standard. 2.1.3 A component shall be used in accordance with its rating established for the intended conditions of use. JUNE 14, 2004 UL 497B 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSI
28、ON FROM UL 2.1.4 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 conditions. 2
29、.2 Units of measurement 2.2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information. 2.2.2 Unless indicated otherwise all voltage and current values mentioned in this standard are root-mean-square (rms). 2.3 Undated references 2.3.1 A
30、ny 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. 3 Glossary 3.1 For the purpose of this standard the following denitions apply. 3.2 APPLIQUE UNIT An arrester assembly provided w
31、ith leads for connection across eld terminals. 3.3 ARRESTER A device intended to limit voltage by use of two or more electrodes in an enclosed medium or a solid-state conductor. It may also contain elements that prevent overheating when carrying fault currents. 3.4 BREAKDOWN The abrupt transition of
32、 the gap resistance from a practically innite value to a relatively low value. In the case of a gap, this is sometimes referred to as sparkover or ignition. 3.5 DIRECT CURRENT (DC) BREAKDOWN VOLTAGE The voltage at which a protector changes from nonconduction to conduction when the DC potential is in
33、creased at a rate of 100 volts per second. 3.6 PROTECTOR A device intended to provide transient protection for low voltage DC or AC circuits. The protector uses a base assembly and an arrester that may be a solid-state device, a gas tube, an air gap unit such as a carbon arrester, or similar device.
34、 AC circuits are dened as audio or alternating- current circuits that are isolated from AC branch circuits by a transformer. JUNE 14, 2004 UL 497B 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONSTRUCTION 4 General 4.1 A circuit protecto
35、r shall be constructed to withstand, without damage, its intended installation and use and shall comply with the performance requirements specied in Sections 11 24. 4.2 A protector mounted or soldered directly to a printed-wiring board shall comply with the spacing requirements in 9.1. When an insul
36、ating barrier or enclosure is used, the material shall be acceptable for the purpose. 4.3 An arrester shall not have provision for adjustment of the electrode gap. 5 Enclosures 5.1 General 5.1.1 An enclosure for protectors shall have the strength and rigidity to resist total or partial collapse with
37、 attendant reduction of spacings, loosening or displacement of parts, or other conditions that could impair the operation of the product or result in a risk of re, electric shock, or injury to persons. 5.1.2 Enclosures for individual components, outer enclosures, and combinations of the two are cons
38、idered in determining compliance with 5.1.1. 5.1.3 A protector enclosure shall have provision for mounting. 5.2 Sheet metal 5.2.1 The thickness of sheet metal used for an enclosure of a protector shall not be less than the applicable value specied in Table 5.1 or 5.2. Exception: Sheet metal of lesse
39、r thickness is not prohibited from being used when, considering the shape, size, and function of the enclosure, it provides equivalent mechanical strength to an enclosure of the thickness specied. JUNE 14, 2004 UL 497B 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION
40、WITHOUT PERMISSION FROM UL 5.3 Nonmetallic 5.3.1 An enclosure of nonmetallic material for a protector shall have the mechanical strength and durability acceptable for the application and be formed so as to cover all current-carrying parts. See the Polymeric Materials Tests, Section 23. Table 5.1 Min
41、imum thickness of sheet metal for electrical enclosures of carbon steel or stainless steel Table 5.1 revised June 14, 2004 Without supporting frame a With supporting frame or equivalent reinforcing a Minimum thickness uncoated, Minimum thickness metal coated, Maximum width, b Maximum length, c Maxim
42、um width, b Maximum length, c inches (cm) inches (cm) inches (cm) inches (cm) inch (mm) inch (mm) 4.0 (10.2) Not limited 6.25 (15.9) Not limited 0.020 (0.51) 0.023 (0.58) 4.75 (12.1) 5.75 (14.6) 6.75 (17.1) 8.25 (21.0) 6.0 (15.2) Not limited 9.5 (24.1) Not limited 0.026 (0.66) 0.029 (0.74) 7.0 (17.8
43、) 8.75 (22.2) 10.0 (25.4) 12.5 (31.8) 8.0 (20.3) Not limited 12.0 (30.5) Not limited 0.032 (0.81) 0.034 (0.86) 9.0 (22.9) 11.5 (29.2) 13.0 (33.0) 16.0 (40.6) 12.5 (31.8) Not limited 19.5 (49.5) Not limited 0.042 (1.07) 0.045 (1.14) 14.0 (35.6) 18.0 (45.7) 21.0 (53.3) 25.0 (63.5) NOTE Sheet steel for
44、 an enclosure intended for outdoor use (watertight) shall be at least 0.036 inch (0.91 mm) thick if zinc- coated and at least 0.032 inch (0.81 mm) thick if uncoated. a A supporting frame is a structure of angle or channel or a folded, rigid section of sheet metal that is rigidly attached to - and ha
45、s essentially the same outside dimensions as - the enclosure surface and that has sufficient torsional rigidity to resist the bending moments that may be applied via the enclosure surface when it is deected. A structure that is as rigid as one built with a frame of angles or channels is considered t
46、o have equivalent reinforcing. Constructions considered to be without supporting frames include: 1) A single sheet with single formed anges (formed edges), 2) A single sheet that is corrugated or ribbed, and 3) An enclosure surface loosely attached to a frame, such as by spring clips. b The width is
47、 the smaller dimension of a rectangular sheet-metal piece that is part of an enclosure. Adjacent surfaces of an enclosure may have supports in common and be made of a single sheet. c For panels that are not supported along one side (for example, side panels of boxes) the length of the unsupported si
48、de shall be limited to the dimensions specied unless the side in question is provided with a continuous ange at least 1/2 inch (12.7 mm) wide. JUNE 14, 2004 UL 497B 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL Table 5.2 Minimum thickness
49、 of sheet metal for electrical enclosures of aluminum, copper, and brass Table 5.2 revised June 14, 2004 Without supporting frame a With supporting frame or equivalent reinforcing a Minimum thickness, Maximum width, b Maximum length, c Maximum width, b Maximum length, c inches (cm) inches (cm) inches (cm) inches (cm) inches (mm) 3.0 (7.6) Not limited 7.0 (17.8) Not limited 0.023 (0.58) 3.5 (8.9) 4.0 (10.2) 8.5 (21.6) 9.5 (24.1) 4.0 (10.2) Not limited 10.0 (25.4) Not limited 0.029 (0.74) 5.0
