SIST-TS CLC/TS 61643-22:2016

SLOVENSKI STANDARD
01-maj-2016
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SIST-TS CLC/TS 61643-22:2007
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Low-voltage surge protective devices - Part 22: Surge protective devices connected to
telecommunications and signalling networks - Selection and application principles
Überspannungsschutzgeräte für Niederspannung - Teil 22: Überspannungsschutzgeräte
für den Einsatz in Telekommunikations- und signalverarbeitenden Netzwerken - Auswahl
und Anwendungsprinzipien
Parafoudres basse tension - Partie 22: Parafoudres connectés aux réseaux de signaux
et de télécommunications - Principes de choix et d'application
Ta slovenski standard je istoveten z: CLC/TS 61643-22:2016
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.

TECHNICAL SPECIFICATION CLC/TS 61643-22

SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
March 2016
ICS 29.240.01; 29.240.10 Supersedes CLC/TS 61643-22:2006
English Version
Low-voltage surge protective devices -
Part 22: Surge protective devices connected to
telecommunications and signalling networks - Selection and
application principles
(IEC 61643-22:2015 , modified)
Parafoudres basse tension -  Überspannungsschutzgeräte für Niederspannung -
Partie 22: Parafoudres connectés aux réseaux de signaux Teil 22: Überspannungsschutzgeräte für den Einsatz in
et de télécommunications - Principes de choix et Telekommunikations- und signalverarbeitenden Netzwerken
d'application - Auswahl und Anwendungsprinzipien
(IEC 61643-22:2015 , modifiée) (IEC 61643-22:2015 , modifiziert)
This Technical Specification was approved by CENELEC on 2016-02-29.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to make the TS available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force.

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.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC/TS 61643-22:2016 E

European foreword
This document (CLC/TS 61643-22:2016) consists of the text of IEC 61643-22:2015 prepared
by SC 37A "Low-voltage surge protective devices" of IEC/TC 37 "Surge arresters", together with the
common modifications prepared by CLC/TC 37A "Low voltage surge protective devices".

This document supersedes CLC/TS 61643-22:2006.

CLCTS 61643-22:2016 includes the following significant technical changes with respect to
CLC/TS 61643-22:2006:
a) Update the use of multiservice SPDs (Article 8)
b) Comparison between SPD classification of EN 61643-11 and EN 61643-21 (7.3.3)
c) Consideration of new transmission systems as PoE (Annex F)
d) EMC requirements of SPDs (Annex G)
e) Maintenance cycles of SPDs (Annex I)

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 61643-22:2015 was approved by CENELEC as a
European Standard with agreed common modifications.

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.
EN 61643-21:2001 + A1:2009 +A2:2013, Low voltage surge protective devices –
Part 21: Surge protective devices connected to telecommunications and signalling networks –
Performance requirements and testing methods (IEC 61643-21:2000 + A1:2008, modified
+A2:2012)
EN 61643-11, Low-voltage surge protective devices – Part 11: Surge protective devices
connected to low-voltage power systems - Requirements and test methods (IEC 61643-11)
EN 61643-12, Low-voltage surge protective devices – Part 12: Surge protective devices
connected to low-voltage power distribution systems – Selection and application principles
(IEC 61643-12)
EN 62305-1:2011, Protection against lightning – Part 1: General principles
(IEC 62305-1:2010, modified)
EN 62305-2:2012, Protection against lightning – Part 2: Risk management
(IEC 62305-2:2010, modified)
EN 62305-3:2011 Protection against lightning – Part 3: Physical damage to structures and life
hazard (IEC 62305-3:2010, modified)
EN 62305-4:2011 Protection against lightning – Part 4: Electrical and electronic systems
within structures (IEC 62305-4:2010, modified)
EN 61000-4-5, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement
techniques – Surge immunity test (IEC 61000-4-5)
7.2 Coupling mechanisms
Replace Table 2 by the following:
Table 2 – Coupling mechanisms
Lightning to
Direct lightning to Lightning to ground Direct lightning
ground near
the structure near the structure to the line
Source of AC
the line
transients influence
(S1) (S2) (S3) (S4)
a
Coupling Resistive Induction Resistive Induction Resistive
Induction
(1) (2) (2) (1, 5) (3) (4)
Voltage wave-
– 1,2/50 1,2/50 – 10/700 50 Hz
shape (µs)
Current wave-
c
10/350 8/20 8/20 10/350 5/320 –
shape (µs)
Preferred
D1 C2 C2 D1 B2 A2
b
category
NOTE (1) – (5) see Figure 3, coupling mechanisms.
a
Also applies for capacitive/inductive couplings of switching in adjoining power supply networks.
b
See Table 3 of EN 61643-21:2001 + A1:2009 + A2:2013.
c The simulated direct lightning strike test impulse is described by the IEC as a peak current value and total
charge. A typical waveshape that can achieve these parameters is a double exponential impulse, 10/350 being
used in this example.
7.3.1.3 Selection of SPDs to reduce transients
Replace Table 3 by the following:
Table 3 – Selection aid for rating SPDs for the use in (zone) interfaces
according to EN 62305-1
Lightning protection zone
LPZ 0/1 LPZ 1/2 LPZ 2/3
EN 62305-1
SPD (j)* D1 --- ---
Requirements to SPDs
B2
(Category from Table 3,
SPD (k)* --- C2/B2 ---
EN 61643-21)
SPD (l)* --- --- C1
* SPD (j, k, l), see Figure 4.
NOTE The range of surge values indicated under LPZ 2/3 includes typical minimum resistibility requirements
and might be implemented into the equipment by market.

Annex B (informative) Current limiting components
B.2.3.2 Heat coils
Replace contents under B.2.3.2 as follows:
Heat coils are thermally activated mechanical components with normally a series and shunt
connection on the line being protected. Their function is to divert current at the circuit
connection point, thereby preventing this current from flowing through the protected
equipment, as shown in Figure B.3. Normally they are constructed using a grounding contact
held in its non-operative position by solder. A heat source, generally a coil of resistance wire
and a spring, force the grounding contact to ground when the solder melts.
The source of heat is the unwanted line current flowing through the coil of resistance wire.
The resistance of communication-type heat coils is typically 4,0 Ω, with a range between
0,4 Ω and 21 Ω. The contact arrangement is such that once the heat coil contacts are closed
(operated) the current flows to earth directly and bypasses the coils.
Heat coils are normally single-operating component. There is no means to restore the line to
its operating state other than the replacement of the item containing the heat coil. Heat coils
have been designed that are manually resettable, not requiring replacement of the SPD. Their
use is generally restricted for application in areas where induced currents from 50 Hz power
systems are frequent.
It is also possible to construct current-interrupting heat coils, which open circuit as a result of
overcurrent.
Time
DUT +i
-i
i
Cabling &
tº
Overcurrent
Equipment
Source
Current Sink
Figure B.3 – Thermally operated (heat coil) three-terminal shunt current limiter
Input
Output
Annex J (informative) Earth potential rise (EPR)
J.2 Causes of EPR
Replace text under J.2 as follows:
Power related EPR is caused by a low frequency, 50 Hz fault current flowing through a ground
grid or the earth via a distribution line power cross to a tree or other earthing paths or utility
switching of power lines. The duration of this event may last from fractions of a second to
many minutes.
Lightning related EPR is caused by a fast rising current of many kA with rise times in nano
seconds to micro seconds and pulse widths in micro seconds to milli seconds flowing through
a ground grid or the earth.
Electrified railways also cause EPR.
IEC 61643-22 ®
Edition 2.0 2015-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –

Part 22: Surge protective devices connected to telecommunications and

signalling networks – Selection and application principles

Parafoudres basse tension –
Partie 22: Parafoudres connectés aux réseaux de signaux et de

télécommunications – Principes de choix et d'application

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.01; 29.240.10 ISBN 978-2-8322-2750-3

– 2 – IEC 61643-22:2015  IEC 2015
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references. 9
3 Terms, definitions and abbreviations . 9
3.1 Terms and definitions . 10
3.2 Abbreviations . 10
4 Description of technologies . 10
4.1 General . 10
4.2 Voltage-limiting components . 10
4.2.1 General . 10
4.2.2 Clamping components . 11
4.2.3 Switching components. 11
4.3 Current-limiting components . 11
4.3.1 General . 11
4.3.2 Current-interrupting components . 11
4.3.3 Current-reducing components. 11
4.3.4 Current-diverting components . 11
5 Parameters for selection of SPDs and appropriate tests from IEC 61643-21 . 12
5.1 General . 12
5.2 Normal service conditions . 12
5.2.1 General . 12
5.2.2 Air pressure and altitude . 12
5.2.3 Ambient temperature . 12
5.2.4 Relative humidity . 12
5.2.5 Abnormal service conditions . 12
5.3 SPD parameters that may affect normal system operation . 12
6 Risk management . 13
6.1 General . 13
6.2 Risk analysis . 14
6.3 Risk identification . 14
6.4 Risk treatment . 14
7 Application of SPDs . 16
7.1 General . 16
7.2 Coupling mechanisms . 16
7.3 Application, selection and installation of surge protective devices (SPDs) . 18
7.3.1 Application requirements for SPDs . 18
7.3.2 SPD installation cabling considerations . 22
7.3.3 Comparison between SPD classification of IEC 61643-11 and
IEC 61643-21 . 25
8 Multiservice surge protective devices . 25
9 Coordination of SPDs/ITE . 28
Annex A (informative) Voltage-limiting components . 29
A.1 Clamping components . 29
A.1.1 General . 29
A.1.2 Metal oxide varistor (MOV) . 29

IEC 61643-22:2015  IEC 2015 – 3 –
A.1.3 Silicon semi-conductors . 29
A.2 Switching components . 31
A.2.1 General . 31
A.2.2 Gas discharge tube (GDT) . 31
A.2.3 Air gaps . 31
A.2.4 Thyristor surge suppressor (TSS) – Fixed voltage types (self-gating) . 32
A.2.5 Thyristor surge suppressor (TSS) – Gated types . 32
Annex B (informative) Current-limiting components . 33
B.1 General . 33
B.2 Non-resetting current limiters . 33
B.2.1 General . 33
B.2.2 Series current-interrupting components . 33
B.2.3 Shunt current-diverting limiters . 34
B.3 Self-resetting current limiters . 36
B.3.1 General . 36
B.3.2 Series current-reducing components . 36
B.3.3 Shunt current-diverting components . 38
Annex C (informative) Risk management . 39
C.1 Risk due to lightning discharges . 39
C.1.1 Risk assessment . 39
C.1.2 Risk analysis. 39
C.1.3 Risk treatment . 41
C.2 Risk due to power line faults . 42
C.2.1 General . 42
C.2.2 AC power systems . 42
C.2.3 DC power systems . 42
Annex D (informative) Transmission characteristics related to IT systems . 44
D.1 General . 44
D.2 Telecommunications systems . 44
D.3 Signalling, measurement and control systems . 45
D.4 Cable TV systems . 45
Annex E (informative) Coordination of SPDs/ITE . 46
E.1 General . 46
E.2 Determination of U and I . 46
IN IN
E.3 Determine the output protective voltage and current waveforms for SPD1 . 47
E.4 Compare SPD1 and SPD2 values . 47
E.5 Necessity of verification of the coordination by testing . 48
Annex F (informative) Protection of Ethernet systems . 49
F.1 Power over Ethernet (PoE) . 49
F.2 Withstand capabilities and SPD coordination . 50
F.3 Common mode to differential mode surge conversion by switching devices . 50
F.3.1 General . 50
F.3.2 Differential mode voltage reduction by inter-wire protection . 51
F.3.3 Differential mode voltage reduction by single switching element . 52
Annex G (informative) EMC impact of SPDs . 54
G.1 General . 54
G.2 Electromagnetic immunity . 54
G.3 Electromagnetic emission . 54

– 4 – IEC 61643-22:2015  IEC 2015
Annex H (informative) Definition of internal port (Source: ITU-T K.44) . 55
Annex I (informative) Maintenance of SPDs for Information Technology . 56
I.1 General requirements . 56
I.2 Maintenance responsibilities . 56
I.3 Maintenance of SPDs . 56
I.3.1 General . 56
I.3.2 Visual inspection . 57
I.3.3 Complete inspection . 57
I.3.4 Examining periods . 57
Annex J (informative) Earth potential rise (EPR) . 59
J.1 General . 59
J.2 Causes of EPR . 59
J.3 Influence of soil resistivity . 59
J.4 Fibre optics . 59
Annex K (informative) References and examples of risk management based on
IEC 62305-2 . 60
Bibliography . 61

Figure 1 – SPD installation in telecommunications and signalling networks . 15
Figure 2 – Measurement and Control network (MCR) . 15
Figure 3 – Coupling mechanisms . 17
Figure 4 – Example of a configuration of the lightning protection concept . 19
Figure 5 – Example of a configuration according to the zones (Figure 4) . 20
Figure 6 – Example of protection measures against common-mode voltages and
differential mode voltages of the data (f) and supply voltage input (g) of an ITE . 21
Figure 7 – Influence of voltages U and U on protection level U caused by
L1 L2 P
inductance of the leads . 22
Figure 8 – Removal of the voltages U and U from the protector unit by connecting
L1 L2
leads to a common point . 23
Figure 9 – Necessary installation conditions of a three, five or multi-terminal SPD with
an ITE for minimizing the interference influences on the protection level . 24
Figure 10 – Individual SPDs . 26
Figure 11 – MSPD with PE connection option . 26
Figure 12 – MSPD with transient bonding SPCs to PE terminals . 27
Figure 13 – Coordination of two SPDs . 28
Figure A.1 – Behaviour of clamping components . 29
Figure A.2 – Behaviour of switching components . 31
Figure B.1 – Behaviour of current interrupting components . 33
Figure B.2 – Behaviour of current-diverting component . 34
Figure B.3 – Thermally operated (heat coil) three-terminal shunt current limiter . 35
Figure B.4 – Behaviour of current-reducing components (thermally operated type) . 36
Figure B.5 – Thermally operated (PTC thermistor) two-terminal series current limiting
component . 37
Figure B.6 – Two-terminal series electronic current limiting component . 38
Figure B.7 – Electronic (gated bidirectional thyristor) three-terminal shunt current
limiting component . 38
Figure C.1 – Risk evaluation procedure . 41

IEC 61643-22:2015  IEC 2015 – 5 –
Figure E.1 – Coordination verification process . 47
Figure F.1 – PoE powering modes . 49
Figure F.2 – Common mode to differential mode surge conversion by asynchronous
SPD operation . 50
Figure F.3 – Differential surge generated by asynchronous SPD operation on a
longitudinal surge . 51
Figure F.4 – SPD circuit with inter-wire protection to limit the differential surge . 51
Figure F.5 – Differential surge voltage limited by inter-wire protection . 52
Figure F.6 – SPD using a single switching element and a steering diode bridge . 52
Figure F.7 – Differential surge voltage reduced by single switching element and
steering diode bridge . 53

Table 1 – Responsibility for managing the protective measures . 14
Table 2 – Coupling mechanisms . 18
Table 3 – Selection aid for rating SPDs for the use in (zone) interfaces according to
IEC 62305-1 . 20
Table 4 – Relationship between SPD classification of IEC 61643-21 and IEC 61643-11 . 25
Table 5 – Relationship between LPZ and the requested test categories of MSPDs . 27
Table C.1 – AC overhead power systems . 42
Table C.2 – AC underground electric cables . 42
Table C.3 – DC overhead power systems . 43
Table C.4 – DC underground electric cables . 43
Table D.1 – Transmission characteristics for telecommunications systems in access
networks . 44
Table D.2 – Transmission characteristics of IT systems in customer premises . 45
Table D.3 – Transmission characteristics of cable TV systems . 45
Table F.1 – Comparison of Type 1 (PoE) and Type 2 PoE+) powering values . 49
Table I.1 – Maximum period between inspections of lightning protective measures
covered by IEC 62305-3 . 57
Table I.2 – Maximum period between inspections of lightning protective measures
covered by ITU-T K.69 [28] . 58

– 6 – IEC 61643-22:2015  IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 22: Surge protective devices connected to
telecommunications and signalling networks –
Selection and application principles

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 61643-22 has been prepared by subcommittee 37A: Low-voltage
surge protective devices, of IEC technical committee 37: Surge arresters.
This second edition cancels and replaces the first edition published in 2004. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Update the use of multiservice SPDs (Article 8)
b) Comparison between SPD classification of IEC 61643-11 and IEC 61643-21 (7.3.3)
c) Consideration of new transmission systems as PoE (Annex F)
d) EMC requirements of SPDs (Annex G)

IEC 61643-22:2015  IEC 2015 – 7 –
e) Maintenance cycles of SPDs (Annex I)
The text of this standard is based on the following documents:
FDIS Report on voting
37A/273/FDIS 37A/277/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
A list of all parts in the IEC 61643 series, published under the general title Low-voltage surge
protector devices, can be found on the IEC website.
The committee has decided that the contents of this amendment and the base 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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 8 – IEC 61643-22:2015  IEC 2015
INTRODUCTION
This International Standard is a guide for the application of SPDs to telecommunications and
signalling lines and those SPDs which have telecom or signalling SPDs in the same enclosure
with power line SPDs (so called multiservice SPDs). Definitions, requirements and test
methods are given in IEC 61643-21. The decision to use SPDs is based on an analysis of the
risks that are seen by the network or system under consideration. Because
telecommunications and signalling systems may depend on long lengths of wire, either buried
or aerial, the exposure to overvoltages from lightning, power line faults and power line/load
switching, can be significant. If these lines are unprotected, the resultant risk to information
technology equipment (ITE) can also be significant. Other factors that may influence the
decision to use SPDs are local regulators and insurance stipulations. This standard provides
indications for evaluating the need for SPDs, the selection, installation and dimensioning of
SPDs and for achieving coordination between SPDs and between SPDs and ITE installed on
telecommunication and signal lines.
Coordination of SPDs assures that a proper interaction between them, as well as between an
SPD and the ITE to be protected will be realized. Coordination requires that the voltage
protection level, U , and let-through current, I , of the initial SPD does not exceed the
p p
resistibility of subsequent SPDs or the ITE.
In general, the SPD closest to the source of the impinging surge diverts most of the surge: a
downstream SPD will divert the remaining or residual surge. The coordination of SPDs in a
system is affected by the operation of the SPDs and the equipment to be protected as well as
the characteristics of the system to which the SPDs are connected.
The following variables should be reviewed when attempting to attain proper coordination:
• waveshape of the impinging surge (impulse or AC);
• ability of the equipment to withstand an overvoltage/overcurrent without damage;
• installation, e.g. distance between SPDs and between SPDs and ITE;
• SPD voltage-protection levels.
The performance of an SPD and its coordination with other SPDs can be affected by exposure
to previous transients. This is especially true for transients which approach the limit of the
capacity of the SPD. If there is considerable doubt concerning the number and severity of the
surges handled by the SPDs under consideration, it is suggested that SPDs with higher
capabilities be used.
One of the direct effects of poor coordination may be bypassing of the SPD closest to the
surge source, with the result that the following SPD will be forced to handle the entire surge.
This can result in damage to that SPD.
Lack of proper coordination can also lead to equipment damage and, in severe cases, may
lead to a fire hazard.
There are several technologies used in the design of the SPDs covered in this standard.
These are explained in the main text and also in informative Annexes A and B.

IEC 61643-22:2015  IEC 2015 – 9 –
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 22: Surge protective devices connected to
telecommunications and signalling networks –
Selection and application principles

1 Scope
This part of IEC 61643 describes the principles for the selection, operation, location and
coordination of SPDs connected to telecommunication and signalling networks with nominal
system voltages up to 1 000 V r.m.s. a.c. and 1 500 V d.c.
This standard also addresses SPDs that incorporate protection for signalling lines and power
lines in the same enclosure (so called multiservice SPDs).
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 61643-21:2012, Low voltage surge protective devices – Part 21: Surge protective devices
connected to telecommunications and signalling networks – Performance requirements and
testing methods
IEC 61643-11, Low-voltage surge protective devices – Part 11: Surge protective devices
connected to low-voltage power systems – Requirements and test methods
IEC 61643-12, Low-voltage surge protective devices – Part 12: Surge protective devices
connected to low-voltage power distribution systems – Selection and application principles
IEC 62305-1:2010, Protection against lightning – Part 1: General principles
IEC 62305-2:2010, Protection against lightning – Part 2: Risk management
IEC 62305-3:2010, Protection against lightning – Part 3: Physical damage to structures and
life hazard
IEC 62305-4:2010, Protection against lightning – Part 4: Electrical and electronic systems
within structures
IEC 61000-4-5, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement
techniques – Surge immunity test
3 Terms, definitions and abbreviations
For the purposes of this document, the following terms, definitions and abbreviations apply.

– 10 – IEC 61643-22:2015  IEC 2015
3.1 Terms and definitions
3.1.1
resistibility
ability of telecommunication equipment or installations to withstand, in general, without
damage, the effects of overvoltages or overcurrents, up to a certain specified extent, and in
accordance with a specified criterion
Note 1 to entry: This definition is derived from ITU-T K.44 [24] .
3.1.2
multiservice surge protective device
MSPD
surge protective device providing protection for two or more services such as power,
telecommunications and signalling in a single enclosure in which a reference bond is provided
between services during surge conditions
3.2 Abbreviations
MSPD Multiservice Surge Protective Device
POTS Plain Old Telephone Service
VDSL Very High Speed Digital Subscriber Line
ADSL Asymmetric Digital Subscriber Line
PoE Power over Ethernet
4 Description of technologies
4.1 General
The following is a short description of various surge protection component technologies. More
details are available in Annexes A and B.
4.2 Voltage-limiting components
4.2.1 General
These shunt-connected SPD components are non-linear elements that limit overvoltages that
exceed a given voltage by providing a low impedance path to divert currents. The continuous
operating voltage (U ), of the SPD is chosen to be greater than the maximum peak system
c
voltage in normal operation. At the maximum system operating voltage, the SPD’s leakage
current shall not interfere with normal system operation.
Multiple components may be used to form assemblies. Connecting voltage-limiting surge
protective components in series may results in higher voltage protection levels. Parallel
component connection may increase the surge current capability of the assembly. For
example, switching components will not share current, however clamping components may.
Some technologies, e.g. metal oxide varistors, have voltage-current characteristics that are
inherently symmetrical for positive and negative voltage polarities. Such components are
classified as symmetrical bi-directional. Components having positive and negative current-
voltage characteristics with the same basic shape, but with significantly different
characteristic values are classified as asymmetrical bi-directional.
Other technologies, e.g. PN semi-conductor components, typically have symmetrical voltage-
current characteristics.
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Numbers in square brackets refer to the Bibliography.

SIST-TS CLC/TS 61643-22:2
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