Description / Abstract:
This International Standard is applicable to devices for surge protection of telecommunications and signalling networks against indirect and direct effects of lightning or other transient overvoltages.
The specifications serve for compliance that the necessary requirements are met by low voltage surge protective devices used for protection in telecommunications and signalling networks. For this purpose, two basic types of circuits for low voltage surge protective devices are taken into consideration: those with exclusively voltage-limiting component and those with voltage- and current-limiting component in an enclosure.
The requirements stipulated for the low voltage surge protective devices concern general requirements for identification and product documentation, marking of low voltage surge protection devices and electrical, mechanical and environmental requirements.
The electrical requirements serve to ensure that the voltage and current-limiting functions as well as the signal transmission capabilities of the low voltage surge protective device fulfill their purpose.
Regarding voltage limitation, requirements for the maximum continuous operating voltage, insulation resistance, voltage limitation during impulse influence, the impulse re-set, AC durability, impulse durability for voltage limiting function, overstressed faults and the blind spot test multi stage SPD are provided.
Regarding current limitation, requirements for the nominal current, the series resistance, response time, current reset time, maximum disconnection voltage, the AC durability for current limiting function and the impulse durability for current limiting function are provided.
Moreover, an operating duty test is specified. Regarding the transmission capabilities, requirements for the capacitance, insertion and return loss, longitudinal balance, bit error ratio and near-end crosstalk loss are provided.
The mechanical requirements serve to ensure that the low voltage surge protective device demonstrates sufficient mechanical strength of the installation, is not damaged by ingress of solid objects, water or fire, and is sufficiently fire-resistant. Moreover, requirements regarding protection against direct contact are specified.
The environmental requirements serve to ensure that the low voltage surge protective device is not damaged by the environmental conditions (temperature, humidity). In order to test whether the low voltage surge protective device meets the requirements, corresponding test methods are specified in this standard.
With respect to the previous version of this standard, a series of individual specifications has been modified and supplemented, including the specified ranges of test temperature and ambient humidity.
Moreover, it has been included in corresponding sections of the standard text that AC low voltage surge protective devices running on alternating current, DC low voltage surge protective devices running on direct current and AC/DC low voltage surge protective devices running on direct current shall be tested.
In addition, two annexes with information regarding basic configurations for measuring the voltage protection level and regarding the subject of resistibility in telecommunication systems have been added.