1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 497 Protectors for Paired-Conductor Communications CircuitsUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL N
2、OT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Protectors for Paired-Conductor Communications Circuits, UL 497 Seventh Edition, Dated April 25, 2001 Summary of Topics This revision is being issued to reaffirm approval of UL 497 as an Amer
3、ican National Standard. No changes in requirements are involved. Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. The revisions are substantially in accordance with Proposal(s) on this subject dated May 17, 2013. A
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6、sing out of the use of or the inability to use this Standard, even if UL or an authorized UL representative has been advised of the possibility of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of t
7、he electronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless from and against any loss, expense, liability, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electroni
8、c 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 requir
9、ements that have been revised and that have a future effective date are located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice. JULY 19, 2013 UL 497 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JULY 19, 2013 U
10、L 497 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL APRIL 25, 2001 (Title Page Reprinted: July 19, 2013) 1 UL 497 Standard for Protectors for Paired-Conductor Communications Circuits The rst fourth editions were tit
11、led Protectors for Communication Circuits. The fth edition was titled Protectors for Paired Conductor Communication Circuits. First Edition March, 1953 Second Edition November, 1965 Third Edition February, 1971 Fourth Edition December, 1978 Fifth Edition February, 1991 Sixth Edition July, 1995 Seven
12、th Edition April 25, 2001 This ANSI/UL Standard for Safety consists of the Seventh Edition including revisions through July 19, 2013. The most recent designation of ANSI/UL 497 as a Reaffirmed American National Standard (ANS) occurred on July 19, 2013. ANSI approval for a standard does not include t
13、he 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-Line Collaborative Standards Development System (CSDS) at ht
14、tp:/. 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 the sole and exclusive property of UL. COPYRIGHT 2013 UNDERWR
15、ITERS LABORATORIES INC. ANSI/UL 497-2004 (R2013)UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JUNE 14, 2004 PROTECTORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR F
16、URTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .7 2 General 8 2.1 Components .8 2.2 Units of measurement .8 2.3 Undated references .8 3 Glossary .8 CONSTRUCTION 4 General .10 5 Enclosures 11 5.1 General 11 5.2 Sheet metal 11 5.3 Nonmetallic .13 5.4 Arres
17、ter well sizes .13 6 Protection Against Corrosion 14 6.1 General 14 6.2 Outdoor use 15 6.3 Grommets 15 7 Field-Wiring Connections .15 7.1 General 15 7.2 Field-wiring terminals 15 7.3 Field-wiring connections (appliqu units) .16 7.4 Field-wiring leads and cables .17 7.5 Field-wiring terminals accessi
18、ble to users 17 8 Components 18 8.1 General 18 8.2 Arrester assemblies 18 8.3 Electrical insulation material 18 9 Spacings 19 10 Fuses .19 PERFORMANCE 11 General 20 12 Line Fuse Current-Carrying Capacity Tests 21 13 Line Fuse Overload Test 22 14 Line Fuse Short-Circuit Test .22 15 Instrument Fuse Li
19、mited Current Tests 23 16 Breakdown Voltage Measurement Test 23 17 Impulse Sparkover Voltage Measurement Test .24 18 Limited Short-Circuit Current Test .25 19 Abnormal Operation Test 27 20 Endurance Conditioning Test .28 21 Induced Low-Current Test .28 22 Sneak Current Test .29 JUNE 14, 2004 PROTECT
20、ORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 23 Gas Tube Arrester Vent Test .30 24 Distortion Test 30 25 Flame Test .30 26 Ultraviolet Light and Water Exposure 31 27 Low Temperatu
21、re Drop 32 28 Rubber Materials Tensile Strength and Elongation Tests 32 29 Air Oven Aging Test 33 30 Ozone Exposure Test .33 31 Indoor Corrosion Test .34 31.1 General .34 31.2 Hydrogen sulde exposure 34 31.3 Sulfur dioxide-carbon dioxide 34 32 Outdoor Corrosion Test 34 32.1 General .34 32.2 Hydrogen
22、 sulde exposure 35 32.3 Sulfur dioxide-carbon dioxide exposure .35 32.4 Salt spray exposure 35 33 Jarring Test 35 34 Water Spray Test .36 35 Drop Test 39 36 Impact Test (Polymeric Enclosures) .39 37 Cover Replacement Test 40 38 Strain Relief Test .40 39 Replacement Arresters Installation Test .40 40
23、 Appliqu Assemblies Installation Test .40 41 Dielectric Voltage-Withstand Test .41 MANUFACTURING AND PRODUCTION-LINE TESTS 42 Gas Tube Seal Test Program 42 42.1 General .42 42.2 Breakdown voltage measurements gas tube seal test program .44 42.3 Mechanical stress test 44 42.4 Thermal aging .44 42.5 T
24、hermal shock .44 42.6 Service life 45 42.7 Over-pressure leak test .45 43 General 46 44 Breakdown Voltage Test .46 MARKING 45 General 46 INSTALLATION INSTRUCTIONS 46 General 47 APRIL 25, 2001 PROTECTORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR
25、 FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL APRIL 25, 2001 PROTECTORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 5 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL This page intentionally le
26、ft blank. JUNE 14, 2004 PROTECTORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements cover protectors for paired-conductor communications circui
27、ts to be used in accordance with Article 800 of the National Electrical Code, NFPA 70. 1.2 As covered by these requirements, a communications circuit protector consists of single- and multiple-pair air gap arresters, gas tube arresters, or solid state arresters, with or without fuses or other voltag
28、e-limiting devices. A circuit protector is intended to protect equipment, wiring, and personnel against the effects of excessive potentials and currents in telephone lines caused by lightning, contacts with power conductors, power induction, and rises in ground potential. 1.3 This standard does not
29、cover the following: a) Lightning protective devices for the protection of secondary distribution wiring systems and equipment. b) Antenna discharge units for radio- and television-receiving appliances. c) Lightning conductor and air terminals for connection of lightning rods for building protection
30、. d) Protectors for re alarm signaling circuits that are covered by the Standard for Protectors for Data Communications and Fire-Alarm Circuits, UL 497B. e) Secondary Protectors for Communications Circuits, UL 497A. f) Transient Voltage Surge Suppressors, UL 1449. 1.4 A product that contains feature
31、s, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of re or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain
32、the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conict with specic requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and
33、 adopted in conformance with the methods employed for development, revision, and implementation of this standard. JUNE 14, 2004 PROTECTORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL
34、 2 General 2.1 Components 2.1.1 Except as indicated in 2.1.2, 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 t
35、he application of the component in the product covered by 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. 2.1.4 Specic components are incomplete in construction feature
36、s 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 Values stated without parentheses are the r
37、equirement. Values in parentheses are explanatory or approximate information. 2.2.2 Unless otherwise indicated, 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 code or standard appearing in the requirements
38、 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 APPLIQU ARRESTER ASSEMBLY An assembly containing two 2-electrode or one 3-electrode gas tube arresters intended for f
39、actory or eld connection on a protector block across a pair of carbon arresters. It is intended to reduce maintenance of carbon arresters by discharging lightning-induced voltages that can cause deterioration of carbon arresters. An appliqu arrester may be constructed to shunt the telephone circuit
40、to earth ground or remove itself from the telephone circuit by fusing open, thus permitting operation of parallel arresters during sustained abnormal line voltage. 3.3 ARRESTER An overvoltage component or assembly of components which permits current ow through it when a designed voltage limit is rea
41、ched. The arrester may consist of a spark gap, gas tube, solid-state component, or the like, coupled with other hardware which serves to support, position, and align the current-carrying components that make up the arrester. 3.4 ARRESTER RATING The breakdown voltage rating specied by the manufacture
42、r. APRIL 25, 2001 PROTECTORS FOR PAIRED-CONDUCTOR COMMUNICATIONS CIRCUITS - UL 497 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 3.5 DIRECT CURRENT (DC) BREAKDOWN VOLTAGE The voltage at which an arrester changes from non-conduction to con
43、duction when the DC potential is increased at a rate not greater than 2000 volts per second. 3.6 FUSE, INSTRUMENT (FUSE, SNEAK CURRENT) A fuse connected in series between the equipment side of an arrester and the telephone equipment that is intended to limit sneak currents. 3.7 FUSE, LINE A fuse con
44、nected in series between a telephone entrance conductor and an arrester and the telephone equipment that is intended to open during a sustained power fault and prevent the protector and ground wire from overheating. The equipment side of the fuse is connected to an arrester. 3.8 FUSE WIRE A conducto
45、r inserted in the telephone outside plant (OSP) if fuseless protectors are installed. The fuse wire is inserted into the connections of the telephone distribution plant between the telephone wire on the pole and the aerial drop wire leading to the building protector. 3.9 FUSIBLE ELEMENT A portion of
46、 an arrester assembly composed of a eutectic alloy that melts on occurrence of a sustained fault, such as a power line contact fault, and permanently shorts the arrester to ground. Other mechanisms that operate and provide a short-circuit mode are also considered fusible elements. 3.10 GAS TUBE SURG
47、E ARRESTER A gap or series of gaps in an enclosed discharge medium, other than air at atmospheric pressure, designed to protect apparatus or personnel or both from high transient voltages. 3.11 GLOW MODE The conductive mode of a gas arrester that exists after breakdown when the circuit impedance lim
48、its the current to a value less than the glow-to-arc transition current. In the glow mode the gas in the arrester is not completely ionized and the voltage across the arrester is greater than the arc voltage but less than the breakdown voltage. 3.12 HEAT COIL A protection device that is used to dete
49、ct low current fault conditions that ow through the protector to the equipment side when the abnormal voltage is insufficient to cause the overvoltage device to shunt the abnormal current to ground. It is comprised of a small gauge wire wound on a metallic bobbin with a shorting pin. When the coil is heated above a predetermined temperature and melts the eutectic alloy holding the pin in position, it grounds or opens the circuit. 3.13 LINE CONDUCTOR A conductor that term
