This standard applies to gas-tube surge-protective device components for application on systems with voltages less than or equal to 1000 V rms or 1200 V dc. These protective devices are designed to limit voltage surges on balanced or unbalanced communication circuits and on power circuits operating from direct current (dc) to 420 Hz. This standard contains a series of standard test criteria for determining the electrical characteristics of gas-tube surge-protective devices.The tests in this standard are intended as design tests as defined in The Authoritative Dictionary of IEEE Standard Terms [B1]1 and provide a means of comparison among various gas-tube surge-protective device components.2Gas-tube devices are used to provide over-voltage protection in electrical circuits. When the breakdown voltage of the gas tube is exceeded@ the normal high-impedance state of the tube changes to a lowimpedance state to allow the gas tube to conduct the surge discharge current. After the tube conducts the surge discharge current@ it interrupts the flow of power follow current and returns to its high-impedance state.This standard??s test criteria and definitions provide a common engineering language that is beneficial to the user and manufacturer of gas-tube surge-protective devices.1The numbers in brackets correspond to those of the bibliography in Annex A. 2In this standard@ the term gas tube or gas-tube surge-protective device component is used when the definition of gas-tube surge arrester (see Clause 2) is intended@ and the term protector is used when the definition of surge protector (see Clause 2) is intended. When a test applies to both protectors and surge-protective device components@ the term device or gas-tube device is used alone. For the purpose of this standard@ all connections to a device are by means of the terminals.