UL 497B BULLETIN

Abstract

These requirements cover protectors for data communications and fire-alarm circuits. <br>As covered by these requirements, data communications circuit protectors and fire-alarm circuit protectors consist of single- and multiple-pair air-gap arresters, gas-tube arresters, or solid-state arresters, with or without fuses or other voltage-limiting devices. Data communications circuit protectors and fire-alarm circuit protectors are intended to protect equipment, wiring, and personnel against the effects of excessive potentials and currents caused by lightning in communications alarm-initiating or alarm-indicating loop circuits. <br>This standard does not cover the following: <br>a) Lightning protective devices for the protection of primary distribution wiring systems and equipment such as AC branch circuit protection. <br>b) Antenna discharge units for radio- and television-receiving appliances. <br>c) Lightning conductor and air terminals for connection of lightning rods for building protection. <br>d) Protective devices to be used on telephone lines or telephone lines connecting to the telecommunication networks. <br>A product that contains features, characteristics, components, materials, or systems new or different from those in use when the standard was developed, and that involves a risk of fire, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the level of safety for the user of the product as originally anticipated by the intent of this Standard.