CLC/TS 61643-12:2006

6/29(16., 6,6776&/&76

67$1'$5'
MDQXDU
1L]NRQDSHWRVWQHQDSUDYH]D]DãþLWRSUHGSUHQDSHWRVWQLPLXGDULGHO
1DSUDYH]D]DãþLWRSUHGSUHQDSHWRVWQLPLXGDUL]DQL]NRQDSHWRVWQHQDSDMDOQH
VLVWHPH±,]ELUDLQQDþHOD]DXSRUDER,(&VSUHPHQMHQ
LVWRYHWHQ&/&76
/RZYROWDJHVXUJHSURWHFWLYHGHYLFHV3DUW6XUJHSURWHFWLYHGHYLFHVFRQQHFWHG
WRORZYROWDJHSRZHUV\VWHPV6HOHFWLRQDQGDSSOLFDWLRQSULQFLSOHV,(&
PRGLILHG
,&6 5HIHUHQþQDãWHYLOND

6,6776&/&76HQ
!"#$%&’( )&!*+,%- .
TECHNICAL SPECIFICATION
CLC/TS 61643-12
SPÉCIFICATION TECHNIQUE
August 2006
TECHNISCHE SPEZIFIKATION
ICS 29.240;29.240.10
English version
Low-voltage surge protective devices
Part 12: Surge protective devices connected
to low-voltage power systems –
Selection and application principles
(IEC 61643-12:2002, modified)
Parafoudres basse tension  Überspannungsschutzgeräte für
Partie 12: Parafoudres connectés aux Niederspannung
réseaux de distribution basse tension – Teil 12: Überspannungsschutzgeräte für
Principes de choix et d'application den Einsatz in Niederspannungsanlagen –
(CEI 61643-12:2002, modifiée)
Auswahl und Anwendungsgrundsätze
(IEC 61643-12:2002, modifiziert)

This Technical Specification was approved by CENELEC on 2006-04-15.

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, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

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

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 61643-12:2006 E

Foreword
The text of the International Standard IEC 61643-12:2002, prepared by SC 37A, Low-voltage
surge protective devices, of IEC TC 37, Surge arresters, together with the common
modifications prepared by CLC 37A was submitted to the formal vote. The combined text was
approved by CENELEC as CLC/TS 61643-12 on 2006-04-15.
The following date was fixed:
– latest date by which the existence of the CLC/TS
has to be announced at national level (doa) 2006-07-01
Annex ZA has been added by CENELEC.

– 3 – CLC/TS 61643-12:2006
CONTENTS
Introduction.6
Keys to understanding the structure of this standard.6
List of variables and abbreviations used in this standard.8
1 Scope.10
2 Normative references .10
3 Definitions .10
4 Systems and equipment to be protected .15
4.1 Low-voltage power distribution systems.15
4.1.1 Lightning overvoltages and currents .16
4.1.2 Switching overvoltages .16
4.1.3 Temporary overvoltages U .17
TOV
4.2 Characteristics of the equipment to be protected .18
5 Surge protective devices .18
5.1 Basic functions of SPDs .18
5.2 Additional requirements.18
5.3 Classification of SPDs .19
5.3.1 SPD: classification.19
5.3.2 Typical design and topologies.19
5.4 Characteristics of SPDs.20
5.4.1 Service conditions described in EN 61643-11 .20
5.4.2 List of parameters for SPD selection.21
5.5 Additional information on characteristics of SPDs.22
5.5.1 Information related to power-frequency voltages.22
5.5.2 Information related to surge currents .22
5.5.3 Information related to voltage protection level provided by SPDs.24
5.5.4 Information related to SPD failure modes .25
5.5.5 Information related to short-circuit withstand .26
5.5.6 Information related to load current I and to voltage drop (for two-
L
port SPDs or one-port SPDs with separate input and output
terminals) .26
5.5.7 Information related to change of characteristics of SPDs .26
6 Application of SPDs in low-voltage power distribution systems .26
6.1 Installation and its effect on the protection given by SPDs.26
6.1.1 Possible modes of protection and installation .27
6.1.2 Influence of the oscillation phenomena on the protective distance .30
6.1.3 Influence of the connecting lead length.30
6.1.4 Need for additional protection.32
6.1.5 Consideration regarding location of the SPD depending on the
classes of test .33
6.1.6 Protection zone concept .33
6.2 Selection of SPD .33
6.2.1 Selection of U , U and I /I /I /U of the SPD .35
n imp max
c T oc
System configuration of distribution network.35
6.2.2 Protective distance .37
6.2.3 Prospective life and failure mode.37
6.2.4 Interaction between SPDs and other devices.38
6.2.5 Choice of the voltage protection level U .39
p
6.2.6 Co-ordination between the chosen SPD and other SPDs .39
6.3 Characteristics of auxiliary devices.41
6.3.1 Disconnecting devices .41
6.3.2 Event counters .42
6.3.3 Status indicator .42
7 Risk analysis .42
8 Co-ordination where equipment has both signalling and power terminals.44
Annex A (informative)  Examples of various SPD technologies .45
A.1 Examples of internal circuits for one port and two port SPDs .45
A.2 Response of SPDs to a combination wave impulse.47
Annex B (informative) Explanation of testing procedures used in EN 61643-11 .48
B.1 Determination of U for SPDs tested in accordance with class I and class II tests .48
res
B.2 Impulse waveshape for assessment of U .48
res
B.3 Influence of a back filter on determination of Ures .48
B.4 Operating duty test for SPDs .49
B.5 TOV failure test .50
B.6 Differences in the testing conditions of Type 1 (test class I), 2 (test class II) and 3
(tests class III) SPDs.50
B.7 short-circuit withstand capability test in conjunction with overcurrent protection (if
any). 51
Annex C (informative) Partial lightning current calculations.52
Annex D (informative) Examples of application of TS 61643-12 .54
D.1 Domestic application .54
D.2 Industrial application .56
D.3 Presence of a lightning protection system.60
Annex E (informative) Examples of application of the risk analysis .61
Annex F (informative)  Consideration for SPDs when Type 1 SPDs are to be applied.64
Annex G (informative)  Immunity vs insulation withstand.65
Annex H (informative) Examples of SPD installation in power distribution boards in
some countries .67
Annex ZA (normative) Normative references to international publications with their
corresponding European publications .70
Bibliography.72

Figure 1 – Examples of components and combinations of components .20
Figure 2 – Relationship between U , U , U and U .22
p 0 c cs
Figure 3 – Typical curve of U versus I for ZnO varistors.24
res
Figure 4 – Typical curve for a spark gap .25
Figure 5 – Flowchart for SPD application .27
Figure 6 – Connection Type 1 .28
Figure 7 – Connection Type 2 .29
Figure 8 – Influence of SPD connecting lead lengths .31
Figure 9 – Need for additional protection .32
Figure 10 – Flowchart for the selection of an SPD .34
Figure 11 – Typical use of two SPDs – Electrical drawing .40

– 5 – CLC/TS 61643-12:2006
Figure A.1 Examples of one-port SPDs .45
Figure A.2 Examples of two-port SPDs .46
Figure A.3 Response of one-port and two-port SPDs to a combination wave impulse.47
Figure C.1 – Simple calculation of the sum of partial lightning currents into the power
distribution system.52
Figure D.1 – Domestic installation.55
Figure D.2 – Industrial installation.58
Figure D.3 – Industrial installation circuitry .59
Figure D.4 – example for a lightning protection system .60
Figure F.1 – General distribution of lightning current.64
Figure H.1 – A wiring diagram of an SPD connected on the load side of the main
incoming isolator via a separate isolator (which could be included in SPD enclosure) .67
Figure H.2 – SPD connected to the nearest available outgoing way (MCB) to the
incoming supply (TNS installation typically seen in the UK).68
Figure H.3 – A single line-wiring diagram of an SPD connected in shunt on the first
outgoing way of the distribution panel via a
...