BS EN 61643-21:2001+A2:2013 Low-voltage surge protective devices – Part 21 Surge protective devices conected to telecommunications and signalling networks

BS EN 61643:21-2001+A2:2013

Low-voltage surge protective devices

Part 21: Surge protective devices conected to telecommunications and signalling networks

National Foreword

This British Standard is the UK implementation of
EN 61643-21:2001+A2:2013.It is derived from IEC 61643-21:2000, incorporating corrigendum March 2001 and amendment 2:2012. It supersedes BS EN 61643-21:2001+A1:2009,which is withdrawn.

The start and finish of text introduced or altered by amendment is indicated in the text by tags. Tags indicating changes to IEC text carry the number of the IEC amendment. For example, text altered by IEC amendment 1 is indicated by A1.

Where a common modification to an IEC amendment has been introduced,the tags carry the number of the amendment.For example, the common modifications introduced by CENELEC to IEC amendment 1 are indicated by C1.

The UK participation in its preparation was entrusted by Technical Committee PEL/37, Surge Arresters – High Voltage, to Subcommittee PEL/37/1, Surge arresters – Low voltage.

A list of organizations represented on this subcommittee can be obtained on request to its secretary.

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.


The purpose of this International Standard is to identify the requirements for Surge Protective Devices (SPDs) used in protecting telecommunication and signalling systen or example ow-voltage data, voice, and alarm circuits. All of these systems may be exposed to the effects of lightning and line faults, either through direct contact or induction. These effects may subject the system to overvoltages or overcurrents or both, whose levels are sufficiently high to harm the system. SPDs are intended to provide protection agains overvoltages and overcurrents caused by lightning and power line faults. This standard describes tests and requirements which establish methods for testing SPDs and determining heir performance.

The SPDs addressed in this International Standard may contain overvoltage protection components only, or a combination of overvoltage and overcurrent protection components Protection devices containing overcurrent protection components only are not within the coverage of this standard. However, devices with only overcurre
covered in annex A.

An SPD may comprise several overvoltage and overcurrent protection components. All SPDs are tested on a “black box” basis, i.e., the number of terminals of the SPD determines the testing procedure, not the number of components in the SPD. The SPD configurations are described in 1.2. In the case of multiple line SPDs, each line may be tested independently of the others, but there may also be a need to test all lines simultaneously.

This standard covers a wide range of testing conditions and requirements; the use of some of these is at the discretion of the user. How the requirements of this standard relate to the different types of SPD is described in 1.3. Whilst this is a performance standard and certain capabilities are demanded of the SPDs, failure rates and their interpretation are left to the user. Selection and application principles will be covered in IEC 61643-22 1).

If the SPD is known to be a single component device, it has to meet the requirements of the relevant standard as well as those in this standard.