1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 497B Protectors for Data Communications and Fire-Alarm Circuits STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULU
2、L COPYRIGHTED MATERIAL 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
3、 to reaffirm ANSI approval of the Standard. The revisions are substantially in accordance with Proposal(s) on this subject dated December 23, 2016. Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. All rights reserv
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8、e purchasers computer system. FEBRUARY 10, 2017 UL 497B tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL FEBRUARY 10, 2017 UL 497B tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITH
9、OUT PERMISSION FROM UL JUNE 14, 2004 (Title Page Reprinted: February 10, 2017) 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 Commu
10、nications 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 February 10, 2017. The most recent designation of ANSI/UL 497B a
11、s a Reaffirmed American National Standard (ANS) occurred on February 10, 2017. ANSI approval for a standard does not include the Cover Page, Transmittal Pages and Title Page. Comments or proposals for revisions on any part of the Standard may be submitted to UL at any time. Proposals should be submi
12、tted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at https:/. 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 r
13、egarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2017 UNDERWRITERS LABORATORIES INC. ANSI/UL 497B-2004 (R2017)UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL FEBRUARY 10, 2017 UL 497B 2 No Text on This P
14、ageUL 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 Enclosures .7 5.1 General 7 5.2 Sh
15、eet 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 Fuses .13 PERFORMANCE 11 Gene
16、ral 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 Test .18 21 Discharge Test 19 2
17、2 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 MARKING 25 General 21 JUNE 1
18、4, 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, data communications circuit pr
19、otectors 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 are intended to protect equip
20、ment, 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 protection of primary distribution wi
21、ring 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 on telephone lines or teleph
22、one 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 to persons shall be evaluated
23、 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 2.1.2, a component of a product
24、 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 this standard, or b) Is supe
25、rseded 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 PERMISSION FROM UL 2.1.4 Specic compo
26、nents 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. 2.2 Units of measurement 2.2.1
27、 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 Any undated reference to a cod
28、e 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 with leads for connection acro
29、ss 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 the gap resistance from a pr
30、actically 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 increased at a rate of 100 volt
31、s 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. AC circuits are dened as aud
32、io 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 protector shall be constructed to wit
33、hstand, 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 insulating barrier or enclosure is
34、 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 attendant reduction of spaci
35、ngs, 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 considered in determining complia
36、nce 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 lesser thickness is not prohibited
37、 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 WITHOUT PERMISSION FROM UL 5.
38、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 Minimum thickness of sheet metal
39、 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 Maximum width, b Maximum length, c
40、 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) 8.75 (22.2) 10.0 (25.4) 12.
41、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 an enclosure intended for ou
42、tdoor 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 has essentially the same outsid
43、e 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 to have equivalent reinforcing
44、. 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 the smaller dimension of a r
45、ectangular 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 side shall be limited to the di
46、mensions 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 of sheet metal for electrica
47、l 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
48、) 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 (12.7) 6.0 (15.2) 10.5 (26.7) 13.5 (34.3) 6.0 (15.2) Not limited 14.0 (35.6) Not limited 0.036 (0.91) 6.5 (16.5) 8.0 (20.3) 15.0 (38.
49、1) 18.0 (45.7) 8.0 (20.3) Not limited 19.0 (48.3) Not limited 0.045 (1.14) 9.5 (24.1) 11.5 (29.2) 21.0 (53.3) 25.0 (63.5) 12.0 (30.5) Not limited 28.0 (71.1) Not limited 0.058 (1.47) 14.0 (35.6) 16.0 (40.6) 30.0 (76.2) 37.0 (94.0) NOTE Sheet copper, brass, or aluminum for an enclosure intended for outdoor use (watertight) shall not be less than 0.029 inch (0.74 mm) thick. a A supporting frame is a structure of angle or channel or a folded rigid section of sheet metal that is rigidly attached to
