EN 61643-311:2013

Components for low-voltage surge protective devices - Part 311: Performance requirements and test circuits for gas discharge tubes (GDT)

IEC 61643-311:2013 is applicable to gas discharge tubes (GDT) used for overvoltage protection in telecommunications, signalling and low-voltage power distribution networks with nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c..They are defined as a gap, or several gaps with two or three metal electrodes hermetically sealed so that gas mixture and pressure are under control. They are designed to protect apparatus or personnel, or both, from high transient voltages. This standard contains a series of test criteria, test methods and test circuits for determining the electrical characteristics of GDTs having two or three electrodes. This standard does not specify requirements applicable to complete surge protective devices, nor does it specify total requirements for GDTs employed within electronic devices, where precise coordination between GDT performance and surge protective device withstand capability is highly critical. This second edition of IEC 61643-311 cancels and replaces the first edition published in 2001. It constitutes a technical revision. Specific changes with respect to the previous edition are: Addition of performance values. Key words: gas discharge tubes (GDT), overvoltage protection in telecommunications, signalling and low-voltage power distribution networks, nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c.

Bauelemente für Überspannungsschutzgeräte für Niederspannung - Teil 311: Leistungsanforderungen sowie Prüfschaltungen und -verfahren für Gasentladungsableiter (ÜsAG)

Composants pour parafoudres basse tension - Partie 311: Exigences de performance et circuits d'essai pour tubes à décharge de gaz (TDG)

La CEI 61643-311:2013 est applicable aux tubes à décharge de gaz (TDG) utilisés pour la protection contre les surtensions des réseaux de télécommunications, de signaux et de distribution basse tension, dont les tensions nominales de réseau sont inférieures ou égales à 1 000 V (valeurs efficaces) c.a. et 1 500 V c.c. Ils sont définis comme un éclateur ou des éclateurs avec deux ou trois électrodes métalliques hermétiquement scellées de sorte que le mélange et la pression de gaz soient sous contrôle. Ils sont conçus pour protéger des matériels ou des personnes, ou les deux, contre des surtensions transitoires élevées. La présente norme contient une série de critères d'essai, de méthodes d'essai et de circuits d'essai destinés à déterminer les caractéristiques électriques des TDG comportant deux ou trois électrodes. La présente norme ne traite pas des exigences applicables aux parafoudres complets, ni de la totalité des exigences relatives aux TDG utilisés dans les dispositifs électroniques, où une coordination précise entre les performances des TDG et la résistance des parafoudres aux surtensions est primordiale. Cette deuxième édition de la CEI 61643-311 annule et remplace la première édition publiée en 2001 dont elle constitue une révision technique. Les changements spécifiques par rapport à l'édition précédente sont: l'ajout des valeurs de performance. Mots clés: tubes à décharge de gaz (TDG), protection contre les surtensions des réseaux de télécommunications, de signaux et de distribution basse tension, tensions nominales sont inférieures ou égales à 1 000 V (valeurs efficaces) c.a. et 1 500 V c.c

Sestavni deli za nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 311. del: Zahtevane lastnosti, preskusni tokokrogi in metode preskušanja plinskih odvodnikov (IEC 61643-311:2013)

Ta del standarda IEC 61643 se uporablja za s plinom polnjene cevi (GDT), ki se uporabljajo za prenapetostno zaščito pri telekomunikacijah, signaliziranju in nizkonapetostnih razdelilnih omrežjih z nazivnimi sistemskimi napetostmi do 1000 V (efektivne izmenične napetosti) izmenične napetosti in 1500 V enosmerne napetosti. Določene so kot reža ali več rež z dvema ali tremi nepredušno zatesnjenimi kovinskimi elektrodami, tako sta zmes plinov in tlak pod nadzorom. Zasnovane so tako, da ščitijo aparat ali osebje ali oboje pred visokimi tranzientnimi napetostmi. Ta standard vsebuje niz preskusnih meril, preskusnih metod in preskusnih tokokrogov za ugotavljanje električnih značilnosti s plinom polnjenih cevi z dvema ali tremi elektrodami. Ta standard ne določa zahtev, ki se uporabljajo za celotne prenapetostne zaščitne naprave, niti ne določa skupnih zahtev za s plinom polnjene cevi, ki se uporabljajo znotraj elektronskih naprav, kjer je natančna koordinacija med delovanjem s plinom polnjenih cevi in odpornostjo prenapetostne zaščitne naprave izjemno kritična. Ta del standarda IEC 61643 – ne obravnava elementov za pritrditev in njihovega vpliva na značilnosti s plinom polnjenih cevi. Navedene značilnosti se uporabljajo izključno za s plinom polnjene cevi, ki so pritrjene na načine, opisane za preskuse; – ne obravnava mehanskih dimenzij; – ne obravnava zahtev za zagotavljanje kakovosti; – morda ne zadostuje za s plinom polnjene cevi, ki se uporabljajo pri visoki frekvenci (>30 MHz); – ne obravnava elektrostatičnih napetosti; –ne obravnava komponent hibridne prenapetostne zaščite ali sestavljenih naprav s cevmi, polnjenimi s plinom.

General Information

• Status: Published
• Publication Date: 08-Aug-2013
• Withdrawal Date: 15-May-2016
• ICS: 31.100 - Electronic tubes
• ICS: 33.040.99 - Other equipment for telecommunication systems
• Technical Committee: CLC/SR 37B - Specific components for surge arresters and surge protective devices
• Drafting Committee: IEC/SC 37B - IEC_SC_37B
• Parallel Committee: IEC/SC 37B - IEC_SC_37B
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 09-Aug-2013
• Completion Date: 09-Aug-2013
• Directive: 2004/108/EC - Directive 2004/108/EC of the European Parliament and of the Council of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2004/108/EU - DIRECTIVE 2004/108/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2014/30/EU - Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to electromagnetic compatibility (recast)
• Ref Project: SIST EN 61643-311:2013 - Components for low-voltage surge protective devices - Part 311: Performance requirements and test circuits and methods for gas discharge tubes (GDT)

Relations

• Replaces: EN 61643-311:2001 - Components for low-voltage surge protective devices - Part 311: Specification for gas discharge tubes (GDT)
• Effective Date: 29-Jan-2023

Overview

EN 61643-311:2013 (IEC 61643-311:2013) specifies performance requirements and test circuits for gas discharge tubes (GDT) used for overvoltage protection in telecommunications, signalling and low‑voltage power distribution networks. It applies to hermetically sealed two‑ and three‑electrode GDTs intended to protect apparatus and personnel from high transient voltages in systems with nominal voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c.. This edition (2013) is a technical revision of the 2001 version with the addition of explicit performance values.

Key topics and technical requirements

• Scope and definitions for GDTs, electrodes and service conditions (temperature, altitude, humidity).
• Mechanical and material requirements: robustness of terminations, solderability, radiation resistance and marking.
• Electrical characteristics measured and specified:
  • Sparkover voltages (DC and impulse) and their test methods
  • Insulation resistance and capacitance measurements
  • Glow‑to‑arc transition current, glow and arc voltages
  • Transverse voltage and DC holdover voltage tests
  • AC follow current behaviour and fail‑short (failsafe) requirements
• Current‑carrying capacity classes and life‑test procedures (nominal impulse and alternating discharge currents, 8/20 and 10/1000 waveforms where applicable).
• Test circuits and procedures: detailed circuits for DC/impulse sparkover, glow‑to‑arc, transverse voltage, holdover and life tests.
• Normative references to related EMC and environmental test standards (e.g. IEC 61000‑4‑5, IEC 60068 series).

Applications and practical value

• Ensures repeatable performance and safety of GDT components in surge protective devices (SPDs) for:
  • Telecom exchanges and cabling, signalling and control systems
  • Low‑voltage power distribution and secondary substations
• Used to specify and verify component performance during design, type testing and production quality control.
• Provides essential test methods for component manufacturers, independent test laboratories and certification bodies to demonstrate compliance with recognized European/IEC practice.
• Helps designers of SPDs and electronic equipment to select appropriate GDTs and plan coordination between GDT behavior and overall surge protection.

Who should use this standard

• GDT and SPD component manufacturers
• Test laboratories and conformity assessment bodies
• Electrical and telecom equipment designers and system integrators
• Procurement teams specifying surge protection components
• Regulatory and safety engineers involved in LV protection

Related standards

• IEC/EN 61643 series (other parts for complete SPDs)
• IEC 61000‑4‑5 (surge immunity test)
• IEC 60068 series (environmental testing)

Keywords: EN 61643-311:2013, IEC 61643-311:2013, gas discharge tubes (GDT), GDT testing, overvoltage protection, surge protective devices, telecommunications surge protection.

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2013
1DGRPHãþD
SIST EN 61643-311:2005
6HVWDYQLGHOL]DQL]NRQDSHWRVWQHQDSUDYH]D]DãþLWRSUHGSUHQDSHWRVWQLPLXGDUL
GHO=DKWHYDQHODVWQRVWLSUHVNXVQLWRNRNURJLLQPHWRGHSUHVNXãDQMDSOLQVNLK
RGYRGQLNRY,(&
Components for low-voltage surge protective devices - Part 311: Performance
requirements and test circuits and methods for gas discharge tubes (GDT)
Composants pour parafoudres basse tension - Partie 311: Circuits et méthodes d'essai
pour tubes à décharge de gaz
Ta slovenski standard je istoveten z: EN 61643-311:2013
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
29.240.10 Transformatorske postaje. Substations. Surge arresters
Prenapetostni odvodniki
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61643-311
NORME EUROPÉENNE
August 2013
EUROPÄISCHE NORM
ICS 31.100; 33.040.99 Supersedes EN 61643-311:2001 (partially)

English version
Components for low-voltage surge protective devices -
Part 311: Performance requirements and test circuits for gas discharge
tubes (GDT)
(IEC 61643-311:2013)
Composants pour parafoudres basse Bauelemente für
tension - Überspannungsschutzgeräte für
Partie 311: Exigences de performance et Niederspannung -
circuits d'essai pour tubes à décharge de Teil 311: Leistungsanforderungen sowie
gaz (TDG) Prüfschaltungen und -verfahren für
(CEI 61643-311:2013) Gasentladungsableiter (ÜsAG)
(IEC 61643-311:2013)
This European Standard was approved by CENELEC on 2013-05-16. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61643-311:2013 E
Foreword
The text of document 37B/113/FDIS, future edition 2 of IEC 61643-311, prepared by SC 37B, "Specific
components for surge arresters and surge protective devices", of IEC TC 37, "Surge arresters" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61643-311:2013.
The following dates are fixed:
• latest date by which the document has (dop) 2014-02-16
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2016-05-16
• latest date by which the national
standards conflicting with the

document have to be withdrawn
This document partially supersedes EN 61643-311:2001.
EN 61643-311:2001:
- addition of performance values.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 61643-311:2013 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60364-5-51:2005 NOTE  Harmonised as HD 60364-5-51:2009 (modified).
IEC 61180-1:1992 NOTE  Harmonised as EN 61180-1:1994 (not modified).
IEC 61643-312 NOTE  Harmonised as EN 61643-312.
IEC 61643-11:2011 NOTE  Harmonised as EN 61643-11:2012 (modified).
IEC 61643-21:2000 NOTE  Harmonised as EN 61643-21:2001 (not modified)
+ A1:2008 + A1:2009 (modified)

- 3 - EN 61643-311:2013
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60068-2-1 2007 Environmental testing - EN 60068-2-1 2007
Part 2-1: Tests - Test A: Cold

IEC 60068-2-20 2008 Environmental testing - EN 60068-2-20 2008
Part 2-20: Tests - Test T: Test methods for
solderability and resistance to soldering heat
of devices with leads
IEC 60068-2-21 2006 Environmental testing - EN 60068-2-21 2006
+ corr. January 2012 Part 2-21: Tests - Test U: Robustness of
terminations and integral mounting devices

IEC 61000-4-5 2005 Electromagnetic compatibility (EMC) - EN 61000-4-5 2006
+ corr. October 2009 Part 4-5: Testing and measurement
techniques - Surge immunity test

ITU-T 2011 Resistibility of telecommunication equipment - -
Recommendation installed in a telecommunications centre to
K.20 overvoltages and overcurrents

IEC 61643-311 ®
Edition 2.0 2013-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Components for low-voltage surge protective devices –

Part 311: Performance requirements and test circuits for gas discharge tubes

(GDT)
Composants pour parafoudres basse tension –

Partie 311: Exigences de performance et circuits d’essai pour tubes à décharge

de gaz (TDG)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 31.100; 33.040.99 ISBN 978-2-83220-678-2

– 2 – 61643-311 © IEC:2013
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and symbols . 7
3.1 Terms and definitions . 7
3.2 Symbols . 10
4 Service conditions . 10
4.1 Low temperature . 10
4.2 Air pressure and altitude . 10
4.3 Ambient temperature . 10
4.4 Relative humidity . 11
5 Mechanical requirements and materials . 11
5.1 Robustness of terminations . 11
5.2 Solderability . 11
5.3 Radiation . 11
5.4 Marking . 11
6 General . 11
6.1 Failure rates . 11
6.2 Standard atmospheric conditions . 11
7 Electrical requirements . 12
7.1 General . 12
7.2 Initial values . 12
7.2.1 Sparkover voltages . 12
7.2.2 Insulation resistance . 13
7.2.3 Capacitance . 13
7.2.4 Transverse voltage . 13
7.2.5 DC holdover . 13
7.3 Requirements after application of load. 13
7.3.1 General . 13
7.3.2 Sparkover voltages . 14
7.3.3 Insulation resistance . 14
7.3.4 AC follow current . 14
7.3.5 Fail-short (Failsafe) . 15
8 Test and measurement procedures and circuits . 15
8.1 DC sparkover voltage . 15
8.2 Impulse sparkover voltage . 16
8.3 Insulation resistance . 16
8.4 Capacitance . 16
8.5 Glow-to-arc transition current, glow voltage, arc voltage . 16
8.6 Transverse voltage . 18
8.7 DC holdover voltage . 19
8.7.1 General . 19
8.7.2 DC holdover voltage values . 21
8.8 Requirements for current-carrying capacity . 22
8.8.1 General . 22

61643-311 © IEC:2013 – 3 –
8.8.2 Nominal alternating discharge current . 22
8.8.3 Nominal impulse discharge current, waveshape 8/20 . 23
8.8.4 Life test with impulse currents, waveshape 10/1 000 . 24
8.8.5 AC follow current . 24
8.9 Fail-short (failsafe) . 25
Bibliography . 27

Figure 1 – Voltage and current characteristics of a GDT . 8
Figure 2 – Symbol for a two-electrode GDT . 10
Figure 3 – Symbol for a three-electrode GDT . 10
Figure 4 – Circuit for d.c. sparkover voltage test at 100 V/s . 15
Figure 5 – Circuit for impulse sparkover voltage at 1 000 V/µs . 16
Figure 6 – Test circuit for glow-to-arc transition current, glow voltage and arc voltage . 17
Figure 7 – Voltage-current characteristic of a typical GDT, suitable for measuring for

example the glow-to-arc transition current, glow voltage, and arc voltage . 18
Figure 8 – Test circuit for transverse voltage . 19
Figure 9 – Test circuit for dc holdover voltage, two-electrode GDTs . 20
Figure 10 – Test circuit for dc holdover voltage, three-electrode GDTs . 20
Figure 11 – Circuit for nominal alternating discharge current, two-electrode GDTs . 23
Figure 12 – Circuit for nominal alternating discharge current, three-electrode GDTs . 23
Figure 13 – Circuit for nominal impulse discharge current, two-electrode GDTs . 23
Figure 14 – Circuit for nominal impulse discharge current, three-electrode GDTs . 23
Figure 15 – Circuit for life test with impulse current, two-electrode GDTs . 24
Figure 16 – Circuit for life test with impulse current, three-electrode GDTs . 24
Figure 17 – Test circuit for alternating follow current . 25
Figure 18 – Test circuit for fail-short (failsafe), two-electrode GDTs . 26
Figure 19 – Test circuit for fail-short (failsafe), three-electrode GDTs . 26

Table 1 – DC and impulse sparkover voltage requirements, initial . 12
Table 2 – Values of sparkover voltages after the tests of Table 5 . 14
Table 3 – Values for different d.c. holdover voltage tests for two-electrode GDTs . 21
Table 4 – Values for different d.c. holdover voltage tests for three-electrode GDTs . 21
Table 5 – Different classes of current-carrying capacity . 22

– 4 – 61643-311 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMPONENTS FOR LOW-VOLTAGE
SURGE PROTECTIVE DEVICES –
Part 311: Performance requirements and
test circuits for gas discharge tubes (GDT)

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61643-311 has been prepared by subcommittee 37B: Specific
components for surge arresters and surge protective devices, of IEC technical committee 37:
Surge arresters.
This second edition of IEC 61643-311 cancels and replaces the first edition published in 2001.
It constitutes a technical revision.
Specific changes with respect to the previous edition are:
– Addition of performance values.

61643-311 © IEC:2013 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
37B/113/FDIS 37B/118/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 61643 series, under the general title Components for low-voltage
surge protective devices can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 61643-311 © IEC:2013
COMPONENTS FOR LOW-VOLTAGE
SURGE PROTECTIVE DEVICES –
Part 311: Performance requirements and
test circuits for gas discharge tubes (GDT)

1 Scope
This part of IEC 61643 is applicable to gas discharge tubes (GDT) used for overvoltage
protection in telecommunications, signalling and low-voltage power distribution networks with
nominal system voltages up to 1 000 V (r.m.s.) a.c. and 1 500 V d.c.They are defined as a
gap, or several gaps with two or three metal electrodes hermetically sealed so that gas
mixture and pressure are under control. They are designed to protect apparatus or personnel,
or both, from high transient voltages. This standard contains a series of test criteria, test
methods and test circuits for determining the electrical characteristics of GDTs having two or
three electrodes. This standard does not specify requirements applicable to complete surge
protective devices, nor does it specify total requirements for GDTs employed within electronic
devices, where precise coordination between GDT performance and surge protective device
withstand capability is highly critical.
This part of IEC 61643
– does not deal with mountings and their effect on GDT characteristics. Characteristics
given apply solely to GDTs mounted in the ways described for the tests;
– does not deal with mechanical dimensions;
– does not deal with quality assurance requirements;
– may not be sufficient for GDTs used on high-frequency (>30 MHz);
– does not deal with electrostatic voltages;
– does not deal with hybrid overvoltage protection components or composite GDT devices.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-2-1:2007, Environmental testing – Part 2: Tests. Tests A: Cold
IEC 60068-2-20:2008, Environmental testing – Part 2: Tests. Test T: Test methods for
solderability and resistance to soldering heat of devices with leads
IEC 60068-2-21:2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devices
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 5: Surge immunity test
ITU-T Recommendation K.20:2011, Resistibility of telecommunication equipment installed in a
telecommunications centre to overvoltages and overcurrents

61643-311 © IEC:2013 – 7 –
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply
3.1.1
arc current
current that flows after sparkover when the circuit impedance allows a current to flow that
exceeds the glow-to-arc transition current
3.1.2
arc voltage
arc mode voltage
voltage drop across the GDT during arc current flow
Note 1 to entry: See Figure 1a region A.
3.1.3
arc-to-glow transition current
current required for the GDT to pass from the arc mode into the glow mode
3.1.4
current turn-off time
time required for the GDT to restore itself to a non-conducting state following a period of
conduction.
Note 1 to entry: This applies only to a condition where the GDT is exposed to a continuous d.c. potential (see d.c.
holdover).
3.1.5
d.c. sparkover voltage
d.c. breakdown voltage
voltage at which the GDT transitions from a high-impedance off to a conduction state when a
slowly rising d.c. voltage up to 2 kV/s is applied
Note 1 to entry: The rate of rise for d.c. sparkover voltage measurements is usually equal or less 2 000 V/s.
3.1.6
d.c. holdover
state in which a GDT continues to conduct after it is subjected to an impulse sufficient to
cause breakdown.
Note 1 to entry: In applications where a d.c. voltage exists on a line. Factors that affect the time required to
recover from the conducting state (current turn-off time) include the d.c. voltage and the d.c. current
3.1.7
d.c. holdover voltage
maximum d.c. voltage across the terminals of a gas discharge tube under which it may be
expected to clear and to return to the high-impedance state after the passage of a surge,
under specified circuit conditions
3.1.8
discharge current
current that flows through a GDT after sparkover occurs
Note 1 to entry: In the event that the current passing through the GDT is alternating current, it will be r.m.s. value.
In instances where the current passing through the GDT is an impulse current, the value will be the peak value.

– 8 – 61643-311 © IEC:2013
3.1.9
discharge voltage
residual voltage of an arrester
peak value of voltage that appears across the terminals of a GDT during the passage of GDT
discharge current
3.1.10
discharge voltage current characteristic
V/I characteristic
variation of peak values of discharge voltage with respect to GDT discharge current
Figure 1c Figure 1a
v
v
V
s
G
V
g
V
e
A
V
a
i
t
A
G
Figure 1b
i
t
IEC  527/13
Legend
V spark-over voltage V arc voltage G glow mode range
s a
V glow voltage V extinction voltage A arc mode range
gl e
Figure 1a – Voltage at a GDT as a function of time when limiting a sinusoidal voltage
Figure 1b – Current at a GDT as a function of time when limiting a sinusoidal voltage
Figure 1c – V/I characteristic of a GDT obtained by combining the graphs of voltage and current
Figure 1 – Voltage and current characteristics of a GDT
3.1.11
extinction voltage
voltage at which discharge (current flow) ceases
3.1.12
fail-short
failsafe
thermally-activated external shorting mechanism

61643-311 © IEC:2013 – 9 –
3.1.13
follow on current
current that the GDT conducts from a connected power source after sparkover
Note 1 to entry: The GDT is expected to extinguish after sparkover to avoid overheating
3.1.14
gas discharge tube
GDT
gap, or several gaps with two or three metal electrodes hermetically sealed so that gas
mixture and pressure are under control, designed to protect apparatus or personnel, or both,
from high transient voltages
3.1.15
glow current
glow mode current
current that flows after breakdown when the circuit impedance limits the follow current to a
value less than the glow-to-arc transition current
Note 1 to entry: See Figure 1a region G.
3.1.16
glow-to-arc transition current
current required for the GDT to pass from the glow mode into the arc mode
Note 1 to entry: See Figure 1a region G.
3.1.17
glow voltage
glow mode voltage
peak value of voltage drop across the GDT when a glow current is flowing
Note 1 to entry: See Figure 1a region G.
3.1.18
impulse sparkover voltage
highest value of voltage attained by an impulse of a designated voltage rate-of-rise and
polarity applied across the terminals of a GDT prior to the flow of the discharge current
3.1.19
impulse waveshape
outline of an electrical surge designated as x/y having a rise time of x µs and a decay time to
half value of y µs
3.1.20
nominal alternating discharge current
current which the GDT is designed to conduct for a defined time
Note 1 to entry: For currents with a frequency of 15 Hz to 62 Hz.
3.1.21
nominal d.c. sparkover voltage
volta
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