UL 497A PDF

Secondary Protectors for Communications Circuits

UL 497A – Secondary Protectors for Communications Circuits

Please note:All interim revisions for this edition available at time of your purchase will be included.

Secondary Protectors for Communications Circuits

UL 497A

1 Scope

1.1 These requirements cover secondary protectors for use in single- or multiple-pair-type communications circuits that are intended to be installed in accordance with Article 800 of the National Electrical Code, ANSI/NFPA 70.

1.2 Secondary protectors are intended to be used in the protected side of telecommunications networks that have an operating rms voltage to ground less than 150 volts and installed or used in accordance with the National Electrical Code, NFPA 70.

1.3 These requirements do not cover telephone protectors that are covered by the Standard for Protectors for Paired-Conductor Communications Circuits, UL 497. These requirements do not cover telephone equipment such as telephone answering devices, residential telephone instruments, telephone dialers, cordless telephones, key systems, and private-branch exchange equipment that is covered by the Standard for Telephone Equipment, UL 1459.

1.4 These requirements do not cover cellular telephones or other receiver/transmitter-type devices. Equipment 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 equipment not classified as telecommunications equipment accessories and that may be connected to a telecommunications 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 building in 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 different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.