UL 497A:2019 PDF Download

The UL 497A:2019 standard provides requirements for secondary protectors used in single- or multiple-pair-type communications circuits. These protectors are intended to be installed in accordance with Article 800 of the National Electrical Code.

The purpose of secondary protectors is to safeguard the protected side of telecommunications networks with an operating voltage to ground less than 150 volts. These protectors must be installed and used in compliance with the National Electrical Code.

It's important to note that this standard does not cover telephone protectors, which are covered by the Standard for Protectors for Paired-Conductor Communications Circuits (UL 497). Additionally, telephone equipment such as answering devices, residential telephone instruments, and key systems are not addressed in this standard as they fall under the scope of the Standard for Information Technology Equipment - Safety - Part 1: General Requirements (UL 60950-1).

Furthermore, the UL 497A:2019 standard does not cover cellular telephones or other receiver/transmitter-type devices, as these are addressed by the Standard for Audio-Video Products and Accessories (UL 1492).

Although primarily intended for telecommunications equipment accessories, these requirements may also be used, either directly or by reference, to investigate other equipment connected to a telecommunications network, as long as they apply to that equipment.

Finally, it is important to adhere to these requirements to ensure the safety and proper functioning of the secondary protectors. Any product that deviates from the standard's requirements may pose a risk of fire, electric shock, or injury to individuals. In such cases, additional component and end-product requirements should be evaluated to maintain the level of safety intended by the standard. Any conflicts with the standard's provisions require proposed revisions to be adopted following the methods employed for the development, revision, and implementation of the standard.