1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNovember 1, 20071SUBJECT 497DOUTLINE OF INVESTIGATIONFORComponent Secondary Protectors for Communications Circuits Used withSpecified Voltage SuppressionIssue No. 1November 1, 2007Summary of Topi
2、csThis is the First issue of the Outline of Investigation for ComponentSecondary Protectors for Communications Circuits Used with SpecifiedVoltage Suppression, Subject 497D, which covers secondary protectorcomponents for communications circuits that are intended to be used ininstallations or circuit
3、s with specified voltage suppression.The UL Foreword is no longer located within the UL Standard. For informationconcerning the use and application of the requirements contained in thisStandard, the current version of the UL Foreword is located onULStandardsInfoNet at: http:/ 2007 UNDERWRITERS LABOR
4、ATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNOVEMBER 1, 2007SUBJECT 497D2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .
5、52 General 6PERFORMANCE3 Reduced Voltage Testing 63.1 General .63.2 Overvoltage test 63.3 Component temperature .6MARKINGS4 General 6NOVEMBER 1, 2007 SUBJECT 497D 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULThis page intentionally left bl
6、ank.NOVEMBER 1, 2007SUBJECT 497D4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 This Outline covers secondary protector components for communications circuits that are intended tobe used in installations or circuits wit
7、h specified voltage suppression. These components are intended tobe used in circuits that are protected by a voltage suppression device that has a suppression voltage,including the high end of any specified tolerance, less than the peak value of the maximum applied rmsfault voltage for the component
8、 This includes circuits with integral voltage suppression components andcircuits protected by a known, appropriate primary protector where the installation of such a primaryprotector is controlled.1.2 These requirements cover components intended for use in circuits electrically connected to signali
9、ngand communications circuits located on the equipment side (protected side) of a primary protector.1.3 These components are investigated using a reduced fault voltage for the Overvoltage Test asrecorded in the test report and identified in the individual certification information. The maximumsuppre
10、ssion-voltage rating, including the high end of any specified tolerance, of the requiredvoltage-suppression device is also included. (Common terms for suppression voltage ratings for varioustechnologies include but are not limited to “Rated Impulse Voltage”, “Maximum Clamping Voltage”,“Clamping Volt
11、age (Vc), “Let-Through Voltage”, “Maximum Continuous Operating Voltage”, “SwitchingVoltage (Vs)” and “Breakdown Voltage”.)1.4 These components are intended to suppress abnormal voltage and/or current conditions that bypassthe preceding voltage suppression device. Current limiting components limit cu
12、rrents to less than thecurrent-carrying capacity of communication wire employed in the communication loop of the protectedpremise. Voltage limiting components may be subjected to excessive currents during their normaloperation and usually require additional overcurrent protection in the end product
13、application.1.5 These components do not normally provide protection for the voltage suppression device needed inthe circuit to limit the voltage to less than the component ratings. They also do not provide protectionagainst excessive currents that may flow during the operation of the preceding volta
14、ge suppressiondevice. Additional overcurrent protection prior to the voltage suppression device may be required. Anysuch overcurrent protection shall not disable the voltage suppression without also disconnecting thecomponents from the signaling or communications circuit.NOVEMBER 1, 2007 SUBJECT 497
15、D 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL2 General2.1 This Outline is to be used in conjunction with in the Standard for Secondary Protectors forCommunications Circuits, UL 497A. With the exception of the modified requirements stated
16、 within thisOutline, devices shall comply with all requirements in UL 497A applicable to secondary protectorcomponents.PERFORMANCE3 Reduced Voltage Testing3.1 General3.1.1 The following tests in the Standard for Secondary Protectors for Communications Circuits, UL 497A,are to be performed using a re
17、duced test voltage based on the voltage ratings of the component beingtested.a) Overvoltage Test, Section 27, andb) Component Temperature, Section 29.3.2 Overvoltage test3.2.1 In 27.1.5 of the Standard for Secondary Protectors for Communications Circuits, UL 497A, the 600volts specified in Tests L1,
18、 L2, L3 and L4 are replaced with a voltage equal to the suppression voltagerating, or, if provided, the continuous fault voltage rating, of the component under test.3.3 Component temperature3.3.1 The test voltage described in 29.14(a) of the Standard for Secondary Protectors forCommunications Circui
19、ts, UL 497A, are to be replaced with the nominal operating voltage rating of thecomponent under test. If the component under test is not intended to be used on a telephone loop circuitwith ringing voltages, the test in 29.14(b) of UL 497A is not required.MARKINGS4 General4.1 A product shall be plain
20、ly marked on the product or smallest unit container with:a) The manufacturers name, trademark, or other descriptive marking by which the organizationresponsible for the product is to be identified andb) A distinctive catalog number or the equivalent.4.2 Ratings for suppression voltage shall be marke
21、d on the product or smallest unit container or shall beprovided on the specification sheet for the device. The electrical ratings are to be expressed in either anominal rating or rating range.NOVEMBER 1, 2007SUBJECT 497D6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION
22、WITHOUT PERMISSION FROM UL4.3 A continuous fault voltage rating and/or the maximum suppression voltage of the requiredvoltage-suppression device (V-peak, including the high end of any specified tolerance) shall be markedon the product or smallest unit container or shall be provided on the specification sheet for the device. Thisrating shall also appear in the certification information for the device.NOVEMBER 1, 2007 SUBJECT 497D 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNOVEMBER 1, 2007SUBJECT 497D8No Text on This Page
