EN 62135-1:2008

SLOVENSKI STANDARD
01-januar-2009
1DGRPHãþD
SIST EN 50063:1996
Oprema za uporovno varjenje - 1. del: Varnostne zahteve za zasnovo, izdelavo in
inštalacijo (IEC 62135-1:2008)
Resistance welding equipment -- Part 1: Safety requirements for the design, manufacture
and the installation
Widerstandsschweißeinrichtungen -- Teil 1: Sicherheitsanforderungen für Entwurf,
Herstellung und Errichtung
Matériels de soudage par résistance -- Partie 1: Exigences de sécurité pour la
conception, la fabrication et l’installation
Ta slovenski standard je istoveten z: EN 62135-1:2008
ICS:
25.160.30 Varilna oprema Welding equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62135-1
NORME EUROPÉENNE
November 2008
EUROPÄISCHE NORM
ICS 25.160 Supersedes EN 50063:1989

English version
Resistance welding equipment -
Part 1: Safety requirements for design, manufacture and installation
(IEC 62135-1:2008)
Matériels de soudage par résistance -  Widerstandsschweißeinrichtungen -
Partie 1: Exigences de sécurité Teil 1: Sicherheitsanforderungen
pour la conception, für die Konstruktion,
la fabrication et l’installation Herstellung und Errichtung
(CEI 62135-1:2008) (IEC 62135-1:2008)

This European Standard was approved by CENELEC on 2008-10-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, 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

© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62135-1:2008 E
Foreword
The text of document 26/377/FDIS, future edition 1 of IEC 62135-1, prepared by IEC TC 26, Electric
welding, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 62135-1 on 2008-10-01.
This European standard supersedes EN 50063:1989 + corrigendum August 1990.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-10-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62135-1:2008 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 60085 NOTE  Harmonized as EN 60085:2008 (not modified).
IEC 60112 NOTE  Harmonized as EN 60112:2003 (not modified).
IEC 60364 NOTE  Harmonized in HD 384 / HD 60364 series (modified).
IEC 60990 NOTE  Harmonized as EN 60990:1999 (not modified).
__________
– 3 – EN 62135-1:2008
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application of this document. 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

1) 2)
IEC 60204-1 - Safety of machinery - Electrical equipment EN 60204-1 2006
(mod) of machines -
Part 1: General requirements
IEC 60364-4-41 2005 Low-voltage electrical installations - HD 60364-4-41 2007
(mod) Part 4-41: Protection for safety - Protection + corr. July 2007
against electric shock
1) 2)
IEC 60364-6 - Low voltage electrical installations - HD 60364-6 2007
(mod) Part 6: Verification
1) 2)
IEC 60439-1 - Low-voltage switchgear and controlgear EN 60439-1 1999
assemblies -
Part 1: Type-tested and partially type-tested
assemblies
1) 2)
IEC 60529 - Degrees of protection provided by EN 60529 1991
enclosures (IP Code) + corr. May 1993

IEC 60664-1 2007 Insulation coordination for equipment within EN 60664-1 2007
low-voltage systems -
Part 1: Principles, requirements and tests

1) 2)
IEC 60664-3 - Insulation coordination for equipment within EN 60664-3 2003
low-voltage systems -
Part 3: Use of coating, potting or moulding for
protection against pollution
1) 2)
IEC 61140 - Protection against electric shock - Common EN 61140 2002
aspects for installation and equipment

1)
ISO 669 - Resistance welding - Resistance welding - -
equipment - Mechanical and electrical
requirements
1) 2)
ISO 5828 - Resistance welding equipment - Secondary EN ISO 5828 2001
connecting cables with terminals connected to
water-cooled lugs - Dimensions and
characteristics
1) 2)
ISO 8205-1 - Water-cooled secondary connection cables EN ISO 8205-1 2002
for resistance welding -
Part 1: Dimensions and requirements for
double-conductor connection cables

1)
Undated reference.
2)
Valid edition at date of issue.

Publication Year Title EN/HD Year

1) 2)
ISO 8205-2 - Water-cooled secondary connection cables EN ISO 8205-2 2002
for resistance welding -
Part 2: Dimensions and requirements for
single-conductor connection cables

1) 2)
ISO 12100-1 - Safety of machinery - Basic concepts, EN ISO 12100-1 2003
general principles for design -
Part 1: Basic terminology, methodology

1) 2)
ISO 12100-2 - Safety of machinery - Basic concepts, EN ISO 12100-2 2003
general principles for design -
Part 2: Technical principles
1) 2)
ISO 13849-1 - Safety of machinery - Safety-related parts EN ISO 13849-1 2006
of control systems -
Part 1: General principles for design

1) 2)
ISO 14121-1 - Safety of machinery - Risk assessment - EN ISO 14121-1 2001
Part 1: Principles
IEC 62135-1
Edition 1.0 2008-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Resistance welding equipment –
Part 1: Safety requirements for design, manufacture and installation

Matériels de soudage par résistance –
Partie 1: Exigences de sécurité pour la conception, la fabrication et l’installation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XB
CODE PRIX
ICS 25.160 ISBN 2-8318-9823-4
– 2 – 62135-1 © IEC:2008
CONTENTS
FOREWORD.5
1 Scope.7
2 Normative references .7
3 Terms and definitions.8
4 Environmental conditions.10
5 Tests .10
5.1 Test conditions.10
5.2 Measuring instruments .10
5.3 Type tests .11
5.4 Routine tests .11
6 Protection against electric shock .11
6.1 General .11
6.2 Insulation .12
6.2.1 General .12
6.2.2 Clearances .12
6.2.3 Creepage distances.13
6.2.4 Insulation resistance.14
6.2.5 Dielectric strength .15
6.2.6 Liquid cooling .16
6.3 Protection against electric shock in normal service (direct contact) .16
6.3.1 General .16
6.3.2 Rated no-load voltage at the output .17
6.3.3 Protection provided by barriers or the enclosure.17
6.3.4 Capacitors .17
6.3.5 Automatic discharge of input capacitors.18
6.3.6 Protective conductor current under normal operation.18
6.4 Protection against electric shock in case of a fault condition (indirect contact) .19
6.4.1 General .19
6.4.2 Protective provisions for welding circuit .21
6.4.3 Internal conductors and connections.33
6.4.4 Touch current in fault condition.33
6.4.5 DC resistance welding equipment operating at mains frequency.34
6.4.6 DC resistance welding equipment operating at medium frequency.34
6.4.7 Continuity of the protective bonding circuit .35
6.5 Additional user requirements .35
6.6 Supply voltage.35
6.7 Conductors of the welding circuit.35
7 Thermal requirements.35
7.1 Heating test.36
7.1.1 Test conditions .36
7.1.2 Tolerances of the test parameters .36
7.1.3 Beginning of the heating test .36
7.1.4 Duration of the test.37
7.2 Temperature measurement.37
7.2.1 Measurements conditions .37
7.2.2 Surface temperature sensor .37

62135-1 © IEC:2008 – 3 –
7.2.3 Resistance .37
7.2.4 Embedded temperature sensor.38
7.2.5 Determination of the ambient temperature (t ).38
a
7.2.6 Determination of cooling liquid temperature (t ).38
a
7.2.7 Recording of temperatures .38
7.3 Limits of temperature rise.38
7.3.1 Windings .38
7.3.2 External surfaces.39
7.3.3 Other components .40
8 Abnormal operation .40
8.1 General requirements.40
8.2 Stalled fan test .40
8.3 Cooling system failure .40
8.4 Overload test.41
9 Provisions against mechanical hazards .41
9.1 General .41
9.2 Risk analysis .41
9.2.1 General .41
9.2.2 Ready to use equipment as in delivery state.41
9.2.3 Equipment not ready to use as in delivery state.41
9.2.4 Equipment not ready to use and designed to be incorporated in a
more complex equipment.42
9.3 Measures .42
9.3.1 Minimum measures.42
9.3.2 Additional measures .42
9.4 Conformity of components.43
9.5 Starting for manual operated equipment .43
10 Instructions and markings.44
10.1 Instructions .44
10.2 Markings .44
Annex A (informative) Nominal voltages of supply networks.45
Annex B (normative)  Construction of supply circuit terminals .46
Annex C (informative) Extrapolation of temperature to time of shutdown.48
Annex D (informative) Example of risk analysis and safety level requirement.49
Annex E (informative) Indirect contact protection in resistance welding equipment.53
Bibliography.60

Figure 1 – Measurement of leakage current .22
Figure 2 – Example of metal screen between windings of the supply circuit and the
welding circuit.23
Figure 3 – Example of protective conductor connected directly to the welding circuit
(single-spot, a.c. current equipment).24
Figure 4 – Example of protective conductor connected directly to welding circuits
(multi-spot, a.c. current equipment) .24
Figure 5 – Example of protective conductor connected direct to welding circuits
(medium-frequency equipment).25
Figure 6 – Example of protective conductor connected to welding circuits through
impedances .26

– 4 – 62135-1 © IEC:2008
Figure 7 – Example of protective conductor connected to welding circuits through
auto-inductances .27
Figure 8 – Example of protective conductor connected to welding circuits through
auto-inductances .27
Figure 9 – Example of current operated residual current device (a.c. current
equipment) .28
Figure 10 – Example of current operated residual current device (medium-frequency
equipment) .29
Figure 11 – Example of current operated residual current device and voltage relay .30
Figure 12 – Example of current operated residual current device and safety voltage
operated relay.31
Figure 13 – Example of safety voltage operated relay .32
Figure 14 – Measuring network for leakage current.34
Figure E.1 – Typical fault current .57
Figure E.2 – Time-to-voltage reference curve .59

Table 1 – Minimum clearances for overvoltage category III .12
Table 2 – Minimum creepage distances .14
Table 3 – Insulation resistance .15
Table 4 – Dielectric test voltages .15
Table 5 – Minimum distance through insulation.21
Table 6 – Continuity of the protective bonding circuit .35
Table 7 – Limits of temperature rise for windings .39
Table 8 – Limits of temperature rise for external surfaces .39
Table B.1 – Range of conductor dimensions to be accepted by the supply circuit
terminals.46
Table B.2 – Spacing between supply circuit terminals .47

62135-1 © IEC:2008 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RESISTANCE WELDING EQUIPMENT –

Part 1: Safety requirements for design,
manufacture and installation
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 62135-1 has been prepared by IEC technical committee 26:
Electric welding.
The text of this standard is based on the following documents:
FDIS Report on voting
26/377/FDIS 26/383/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.

– 6 – 62135-1 © IEC:2008
The list of all the parts of the IEC 62135 series, under the general title Resistance welding
equipment, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
62135-1 © IEC:2008 – 7 –
RESISTANCE WELDING EQUIPMENT –

Part 1: Safety requirements for design,
manufacture and installation
1 Scope
This part of IEC 62135 applies to equipment for resistance welding and allied processes and
includes single and multiple welding stations which may be manually or automatically loaded
and/or started.
This standard covers stationary and portable equipment.
It specifies safety requirements for design, manufacture and installation.
To comply with this standard, all safety risks involved in loading, feeding, operating and
unloading the equipment, where applicable, should be assessed and the requirements of
related standards should be observed.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 62135. For dated references, only the edition cited
applies. For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60204-1, Safety of machinery – Electrical equipment of machines – Part 1: General
requirements
IEC 60364-4-41:2005, Low-voltage electrical installations – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-6, Low-voltage electrical installations – Part 6: Verification
IEC 60439-1, Low-voltage switchgear and controlgear assemblies – Part 1: Type-tested and
partially type-tested assemblies
IEC 60529, Degrees of protection provided by enclosures (IP code)
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60664-3, Insulation coordination for equipment within low-voltage systems – Part 3: Use
of coating, potting or moulding for protection against pollution
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
ISO 669, Resistance welding – Resistance welding equipment – Mechanical and electrical
requirements
– 8 – 62135-1 © IEC:2008
ISO 5828, Resistance welding equipment – Secondary connecting cables with terminals
connected to water-cooled lugs – Dimensions and characteristics
ISO 8205-1, Water-cooled secondary connection cables for resistance welding – Part 1:
Dimensions and requirements for double-conductor connection cables
ISO 8205-2, Water-cooled secondary connection cables for resistance welding – Part 2:
Dimensions and requirements for single-conductor connection cables
ISO 12100-1, Safety of machinery – Basic concepts, general principles for design – Part 1:
Basic terminology, methodology
ISO 12100-2, Safety of machinery – Basic concepts, general principles for design – Part 2:
Technical principles
ISO 13849-1, Safety of machinery – Safety-related parts of control systems – Part 1: General
principles for design
ISO 14121-1, Safety of machinery – Risk assessment – Part 1: Principles
3 Terms and definitions
For the purposes of this document, the following terms and definitions, together with those
given in ISO 669, IEC 60664-1 and IEC 60204-1, apply.
3.1
equipment for resistance welding and allied processes
equipment associated with carrying out the processes of resistance welding or allied
processes consisting of, for example, power source, electrodes, tooling and associated
control equipment
NOTE 1 It may be a separate unit or part of a complex machine.
NOTE 2 The term "resistance welding equipment" is used in the following text.
3.2
processes allied to resistance welding
processes carried out on machines comparable to resistance welding equipment considered
as allied to resistance welding, for example, resistance brazing, soldering or heating
3.3
type test
test of one or more devices made to a given design, to check if these devices comply with the
requirements of the standard concerned
[IEV 851-02-09]
3.4
routine test
test made on each individual device during or after manufacture to check if it complies with
the requirements of the standard concerned or the criteria specified
[IEV 851-02-10]
3.5
welding circuit
conductive material through which the welding current is intended to flow

62135-1 © IEC:2008 – 9 –
3.6
control circuit
circuit for the operational control of welding equipment, and/or for protection of the power
circuits
3.7
conventional value
standardized value that is used as a measure of a parameter for the purposes of comparison,
calibration, testing, etc.
NOTE Conventional values do not necessarily apply during the actual welding process.
3.8
rated value
value assigned, generally by the manufacturer, for a specified operating condition of a
component, device or equipment
3.9
rating
set of rated values and operating conditions
3.10
hand-held equipment
resistance welding equipment with built-in or external transformer, which is intended to be
held in the hand during use, suspended or not
3.11
portable equipment
resistance welding equipment that is connected to the mains supply by means of a plug.
3.12
stationary equipment
resistance welding equipment permanently connected to the mains supply
3.13
material group
materials are separated into four groups by their comparative tracking index (CTI) values, as
follows:
Material group I 600 ≤ CTI
Material group II 400 ≤ CTI < 600
Material group IIIa 175 ≤ CTI < 400
Material group IIIb 100 ≤ CTI < 175
The CTI values above refer to values in accordance with IEC 60112.
NOTE For inorganic insulating materials, for example, glass or ceramics, which do not track, creepage distances
need not be greater than their associated clearance for the purpose of insulation coordination.
3.14
thermal equilibrium
state reached when the observed temperature rise of any part of the welding equipment does
not exceed 2 K/h
3.15
thermal protection
system intended to ensure the protection of all or part of the welding equipment against
excessive temperatures resulting from certain conditions of thermal overload

– 10 – 62135-1 © IEC:2008
NOTE It is capable of being reset (either manually or automatically) when the temperature falls to the reset value.
3.16
supply circuit
conductive material of the power source through which the supply current is intended to flow
3.17
general visual inspection
inspection by eye to verify that there are no apparent discrepancies with respect to provisions
of the standard concerned
3.18
working voltage
highest r.m.s. value of the a.c. or d.c. voltage across any particular insulation which can occur
when the equipment is supplied at rated voltage
NOTE 1 Transients are disregarded.
NOTE 2 Both open-circuit conditions and normal operating conditions are taken into account.
4 Environmental conditions
Resistance welding equipment complying with this standard shall be safe to operate under the
following service conditions.
a) At an ambient air temperature from 5 °C to 40 °C at a relative humidity of
– up to 50 % at 40 °C;
– up to 90 % at 20 °C.
The ambient air shall be free from excessive amounts of dust, acids, corrosive gases or
substances etc. other than those generated by the welding process. These environmental
conditions apply to equipment intended for indoor use only.
b) The temperature of the cooling medium does not exceed
1) in the case of a liquid: 30 °C at the inlet;
2) in the case of the ambient air: 40 °C.
c) The altitude above sea-level does not exceed 1 000 m.
NOTE Different environmental conditions may be agreed upon between the manufacturer and the purchaser and
the resulting welding equipment so marked. Examples of these conditions are: outdoor use, different altitude,
different temperature of cooling medium, high humidity, unusually corrosive fumes, steam, excessive oil vapour,
abnormal vibration or shock, excessive dust, unusual sea coast or shipboard conditions.
5 Tests
5.1 Test condition
The tests shall be carried out on new, dry and completely assembled resistance welding
equipment at an ambient air temperature between 10 °C and 40 °C. It is recommended that
the thermal tests be carried out at 40 °C. Liquid-cooled resistance welding equipment shall be
tested with liquid conditions as specified by the manufacturer.
5.2 Measuring instruments
The accuracy of measuring instruments shall be as follows.
a) Electrical measuring instruments: class 0,5 (±0,5 % of full-scale reading), except for the
measurement of insulation resistance and dielectric strength where the accuracy of the
instruments is not specified, but shall be taken into account for the measurement.
b) Instruments for measuring welding current: class 5.

62135-1 © IEC:2008 – 11 –
c) Temperature measuring instruments: ±2 K.
5.3 Type tests
Unless otherwise specified, the tests in this standard are type tests.
The resistance welding equipment shall be tested with all ancillary equipment fitted that could
affect the test results.
All type tests shall be carried out on the same resistance welding equipment except where it
is specified that a test may be carried out on another resistance welding equipment.
As a condition of conformity, the type tests given below shall be carried out in the following
sequence:
a) general visual inspection, see 3.17;
b) insulation resistance, see 6.2.4 (preliminary check);
c) protection provided by the enclosure, see 6.3.3;
d) insulation resistance, see 6.2.4;
e) dielectric strength, see 6.2.5;
f) general visual inspection, see 3.17.
The other tests included in this standard and not listed here may be carried out in any
convenient sequence.
5.4 Routine tests
All routine tests shall be carried out on each resistance welding equipment. The following
sequence is recommended:
a) general visual inspection, see 3.17;
b) continuity of the protective circuit, see 6.4.7;
c) dielectric strength, see 6.2.5;
d) no-load voltage, see 6.3.2;
e) test to ensure rated minimum and maximum output values in accordance with ISO 669;
f) general visual inspection, see 3.17.
6 Protection against electric shock
6.1 General
Hazardous-live-parts shall not be accessible and accessible conductive parts shall not be
hazardous live
– either under normal conditions (operation in intended use, and absence of a fault); or
– under single-fault conditions.
The requirements for provisions for normal conditions protection are given in 6.3.
6.4.
The requirements for provisions for fault condition protection are given in

– 12 – 62135-1 © IEC:2008
6.2 Insulation
6.2.1 General
The majority of resistance welding equipment falls within overvoltage category III in
accordance with IEC 60664-1. All resistance welding equipments shall be designed for use in
environmental conditions of pollution degree 3 as a minimum.
Design of liquid cooled equipment shall consider possible condensation which may require
different conditions.
Components or subassemblies with clearances or creepage distances corresponding to
pollution degree 2 are permitted, if they are completely coated, potted or moulded in
accordance with IEC 60664-3.
Equipment designed with insulation based on line-to-eutral voltage values shall be provided
with a caution that such equipment shall only be used on a supply system that is either a
three-phase, four-wire system with an earthed neutral or a single-phase, three-wire, system
with an earthed neutral.
6.2.2 Clearances
For basic insulation or supplementary and reinforced insulation, minimum clearances shall be
in accordance with IEC 60664-1, as partially summarized in Table 1 for overvoltage category
III.
Table 1 – Minimum clearances for overvoltage category III
Basic or supplementary insulation Reinforced insulation
Rated AC test Pollution degree Rated AC test Pollution degree
Voltage impulse voltage impulse voltage
test 2 3 4 test 2 3 4
voltage   voltage
Clearance Clearance
V r.m.s. Peak V V r.m.s. mm Peak V V r.m.s. mm
50 800 566 0,2 1 500 1 061 0,5 0,8
0,8 1,6
100 1 500 1 061 0,5 1,6 2 500 1 768 1,5
150 2 500 1 768 1,5 4 000 2 828 3
300 4 000 2 828 3 6 000 4 243 5,5
600 6 000 4 243 5,5 8 000 5 657 8
1 000 8 000 5 657 8 12 000 8 485 14
NOTE 1 Values taken from Tables F.1 and F.2 of IEC 60664-1.

NOTE 2 For other pollution degrees and overvoltage categories, see IEC 60664-1.
See Annex A for voltage value.
For dimensioning clearances to accessible non-conductive surfaces, such surfaces shall be
considered to be covered by metal foil wherever they can be touched by the standard test
finger in accordance with IEC 60529.
Clearances shall not be interpolated.
For supply circuit terminals, see Annex B.
Clearances between parts of resistance welding equipment (for example, circuits or
components) which are protected by an overvoltage limiting device (for example, oxide
varistor) may be rated in accordance with overvoltage category I (see IEC 60664-1).

62135-1 © IEC:2008 – 13 –
The values of Table 1 shall also apply to control circuits when separated from the supply
circuit, for example, by a transformer.
If the control circuit is connected direct to the supply circuit, the values for the supply voltage
shall apply.
Conformity shall be checked by measurement in accordance with 6.2 of IEC 60664-1 or where
this is not possible, by submitting the welding equipment to an impulse test using the voltages
given in Table 1.
For the impulse test, a minimum of three impulses of each polarity at the voltage given in
Table 1 are applied with an interval of at least 1 s between impulses using a generator with an
output waveform of 1,2/50 μs and an output impedance of less than 500 Ω.
Alternatively, either an a.c. test voltage as given in Table 1 may be applied for three cycles or
a ripple free d.c. voltage, the value of which is equal to the impulse voltage, may be applied
three times for 10 ms, for each polarity.
The equipment shall withstand the test voltages without any flashover or breakdown.
6.2.3 Creepage distances
For basic insulation or supplementary insulation, minimum creepage distances shall be in
accordance with IEC 60664-1, as summarized in Table 2.
Creepage distances for reinforced or double insulation shall be twice those determined for
basic insulation.
For the purpose of dimensioning creepage distances to accessible surfaces of insulation
material, such surfaces shall be considered to be covered by metal foil wherever they can be
touched by the standard test finger in accordance with IEC 60529.
Creepage distances are given for the highest rated voltage of each line of Table 2. In the case
of a lower rated voltage, interpolation is allowed.
For supply circuit terminals, see Annex B.
The values of Table 2 shall also be applicable to control circuits when separated from the
supply circuit by, for example, a transformer.
A creepage distance cannot be less than the associated clearance, so the shortest possible
creepage distance is equal to the required clearance.
If the control circuit is connected directly to the supply circuit, the values for the supply
voltage shall apply.
Conformity shall be checked by linear measurement in accordance with 6.2 of IEC 60664-1.

– 14 – 62135-1 © IEC:2008
Table 2 – Minimum creepage distances
Creepage distances in millimetres
Basic or supplementary insulation
Printed wiring
material
Pollution degree
Working Pollution degree
voltage 1 2 1 2 3 4
Material Group Material Group Material Group
a b a
I II III I II III I II III
V r.m.s mm mm mm mm mm mm mm mm mm mm mm mm
10 0,025 0,04 0,08 0,4 0,4 0,4 1 1 1 1,6 1,6 1,6
12,5 0,025 0,04 0,09 0,42 0,42 0,42 1,0 1,05 1,05 1,6 1,6 1,6
16 0,025 0,04 0,1 0,45 0,45 0,45 1,1 1,1 1,1 1,6 1,6 1,6
20 0,025 0,04 0,11 0,48 0,48 0,48 1,2 1,2 1,2 1,6 1,6 1,6
25 0,025 0,04 0,12 0,5 0,5 0,5 1,2 1,25 1,25 1,7 1,7 1,7
32 0,025 0,04 0,14 0,53 0,53 0,53 1,3 1,3 1,3 1,8 1,8 1,8
40 0,025 0,04 0,16 0,56 0,8 1,1 1,4 1,6 1,8 1,9 2,4 3
50 0,025 0,04 0,18 0,6 0,85 1,2 1,5 1,7 1,9 2 2,5 3,2
63 0,04 0,063 0,2 0,63 0,9 1,25 1,6 1,8 2 2,1 2,6 3,4
80 0,063 0,1 0,22 0,67 0,95 1,3 1,7 1,9 2,1 2,2 2,8 3,6
100 0,1 0,16 0,25 0,71 1 1,4 1,8 2 2,2 2,4 3 3,8
125 0,16 0,25 0,28 0,75 1,05 1,5 1,9 2,1 2,4 2,5 3,2 4
160 0,25 0,4 0,32 0,8 1,1 1,6 2 2,2 2,5 3,2 4 5
200 0,4 0,63 0,42 1 1,4 2 2,5 2,8 3,2 4 5 6,3
250 0,56 1 0,56 1,25 1,8 2,5 3,2 3,6 4 5 6,3 8
320 0,75 1,6 0,75 1,6 2,2 3,2 4 4,5 5 6,3 8 10
400 1 2 1 2 2,8 4 5 5,6 6,3 8 10 12,5
500 1,3 2,5 1,3 2,5 3,6 5 6,3 7,1 8 10 12,5 16
630 1,8 3,2 1,8 3,2 4,5 6,3 8 9 10 12,5 16 20
800 2,4 4 2,4 4 5,6 8 10 11 12,5 16 20 25
1 000 3,2 5 3,2 5 7,1 10 12,5 14 16 20 25 32
1 250  4,2 6,3 9 12,5 16 18 20 25 32 40
1 600  5,6 8 11 16 20 22 25 32 40 50
2 000  7,5 10 14 20 25 28 32 40 50 63
2 500  10 12,5 18 25 32 36 40 50 63 80
3 200  12,5 16 22 32 40 45 50 63 80 100
4 000  16 20 28 40 50 56 63 80 100 125
5 000  20 25 36 50 63 71 80 100 125 160
6 300  25 32 45 63 80 90 100 125 160 200
8 000  32 40 56 80 100 110 125 160 200 250
10 000  40 50 71 100 125 140 160 200 250 320
a
Material group I, II, IIIa and IIIb.
b
Material group I, II and IIIa.

6.2.4 Insulation resistance
The insulation resistance shall be not less than the values given in Table 3.

62135-1 © IEC:2008 – 15 –
Table 3 – Insulation resistance
Supply circuit (including control circuits welding circuit (including control
to
5 MΩ
connected to it) with protection provision circuits connected to it)
specified in 6.4.2.2
Supply circuit (including control circuits
...