UL 497A:2001 pdf download Secondary Protectors for Communications Circuits
1 Scope
1.1 These requirements cover secondary protectors for use in single- or multiple-pair-typecommunications circuits that are intended to be installed in accordance with Article 800 of the NationaElectrical Code，ANSI/NFPA 70
1.2 Secondary protectors are intended to be used in the protected side of telecommunications networksthat have an operating rms voltage to ground less than 150 volts and installed or used in accordance withthe National Electrical Code,NFPA 70.
1.3 These requirements do not cover telephone protectors that are covered by the Standard forProtectors for Paired-Conductor Communications Circuits, UL 497. These requirements do not covelelephone equipment such as telephone answering devices, residential telephone instruments, telephonedialers, cordless telephones, key systems, and private-branch exchange equipment that is covered by theStandard for Telephone Equipment,UL 1459.
1.4 These requirements do not cover cellular telephones or other receiver/transmitter-type devicesEquipment of this type is covered by the Standard for Radio Receivers, Audio Systems, and Accessories.UL 1270.
1.5 These requirements may be used, directly or by reference, to investigate portions of other equipmentnot classified as telecommunications equipment accessories and that may be connected to atelecommunications network, insofar as they may be applicable to such equipment.
1.6 These requirements do not cover wires and cables intended to be permanently installed in a buildingin accordance with Article 800 of the National Electrical Code. NFPA 70
1.7 A product that contains features, characteristics, components, materials, or systems new or diferentfrom those covered by the requirements in this standard, and that involves a risk of fire or of electric shockor injury to persons shall be evaluated using appropriate additional component and end-productrequirements to maintain the level of safety as originally anticipated by the intent of this standard.Aproduct whose features, characteristics, components, materials, or systems conflict with specificreauirements or provisions of this standard does not comply with this standard. Revision of requirementsshall be proposed and adopted in conformance with the methods employed for development, revision, andimplementation of this standard.
2 General
2.1 Components
21.1 Except as indicated in 2.1.2, a component of a product covered by this standard shall comply withthe requirements for that component. See Appendix A for a list of standards covering components useoin the products covered by this standard.
2.1.2 A component is not required to comply with a specific requirement that:
a) lnvolves a feature or characteristic not required in the application of the component in theproduct covered by this standard,or
b) ls 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 ofuse.
2.1.4 Specific components are incomplete in construction features or restricted in performancecapabilities. Such components are intended for use only under limited conditions, such as certaintemperatures not exceeding specified limits, and shall be used only under those specific conditions.
22 Units of measurement
2.2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.
2.2.2 Unless otherwise indicated. all voltage and current values specified in this standard areroot-mean-square(rms).
2.3 Undated references
2.3.1 Any undated reference to a code or standard appearing in the requirements of this standard shallbe interpreted as referring to the latest edition of that code or standard.
UL 497A:2001 pdf download
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