IEC 62135-1:2015
(Main)Resistance welding equipment - Part 1: Safety requirements for design, manufacture and installation
Resistance welding equipment - Part 1: Safety requirements for design, manufacture and installation
IEC 62135-1:2015 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 second edition cancels and replaces the first edition published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- creepage distances for pollution degree 4 are no longer valid (see Table 2);
- insulation requirements for Class II equipment are defined (see Table 3);
- dielectric test voltage interpolation restriction lower limit is changed to 220 V and interpolation for control and welding circuit is clarified (see Table 4);
- maximum temperature for insulation systems are reviewed in accordance with current edition of IEC 60085 (see Table 7);
- marking of terminals is defined (see 10.3);
- table for nominal voltages of supply networks is changed adopting Table B.2 of IEC 60664-1:2007 in place of the Table B.1 values referenced in the previous edition to provide for equipment to be connected to both earthed and unearthed systems. The change impacts the creepage and clearance distance requirements for some supply voltage ratings (see Annex A);
- touch current in fault condition are measurement procedures are clarified (see 6.4.4 and Annex C);
- welding circuit touch current is defined (see 6.2.6);
- touch current in normal condition are clarified and moved in protection against electric shock in normal service (see 6.3.7);
- heating test conditions are clarified (see 7.1.1);
- external surface temperature rise limitation is changed (see 7.3.2). The contents of the corrigendum of February 2016 have been included in this copy.
Matériels de soudage par résistance - Partie 1: Exigences de sécurité pour la conception, la fabrication et l'installation
L'IEC 62135-1:2015 s'applique aux matériels de soudage par résistance et aux procédés connexes et comprend les stations de soudage simples et multiples qui peuvent être alimentées manuellement ou automatiquement et/ou mises en route. Cette deuxième édition annule et remplace la première édition parue en 2008. Cette édition constitue une résivion technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- les lignes de fuite pour le degré de pollution 4 ne sont plus valables (voir le Tableau 2);
- les exigences relatives à l'isolement pour le matériel de classe II sont définies (voir le Tableau 3);
- la limite inférieure de restriction d'interpolation de la tension d'essai diélectrique est modifiée à 220 V et l'interpolation des circuits de commande et de soudage est clarifiée (voir le Tableau 4);
- la température maximale pour les systèmes d'isolation est revue conformément à l'actuelle édition de l'IEC 60085 (voir le Tableau 7);
- le marquage des bornes est défini (voir 10.3);
- le tableau des tensions nominales des réseaux d'alimentation est modifié: les valeurs du Tableau B.2 de l'IEC 60664-1:2007 sont prises en compte à la place des valeurs du Tableau B.1, référencées dans la précédente édition pour le matériel à connecter aux systèmes mis à la terre et non mis à la terre. Cette modification influence les exigences relatives aux lignes de fuite et aux distances d'isolement dans l'air pour certaines caractéristiques assignées de tension d'alimentation (voir l'Annexe A);
- les informations relatives au courant de contact en cas de défaut et les procédures de mesure sont clarifiées (voir 6.4.4 et l'Annexe C);
- le courant de contact du circuit de soudage est défini (voir 6.2.6);
- les informations relatives au courant de contact en condition normale sont clarifiées et déplacées dans la partie protection contre les chocs électriques en service normal (voir 6.3.7);
- les conditions d'essai d'échauffement sont clarifiées (voir 7.1.1);
- la limite d'échauffement de la surface externe est modifiée (voir 7.3.2). Le contenu du corrigendum de février 2016 a été pris en considération dans cet exemplaire.
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IEC 62135-1 ®
Edition 2.0 2015-05
INTERNATIONAL
STANDARD
colour
inside
Resistance welding equipment –
Part 1: Safety requirements for design, manufacture and installation
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IEC 62135-1 ®
Edition 2.0 2015-05
INTERNATIONAL
STANDARD
colour
inside
Resistance welding equipment –
Part 1: Safety requirements for design, manufacture and installation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.160 ISBN 978-2-8322-2664-3
– 2 – IEC 62135-1:2015 © IEC 2015
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Environmental conditions . 11
5 Tests . 11
5.1 Test condition . 11
5.2 Measuring instruments . 11
5.3 Type tests . 12
5.4 Routine tests. 12
6 Protection against electric shock . 12
6.1 General . 12
6.2 Insulation . 13
6.2.1 General . 13
6.2.2 Clearances . 13
6.2.3 Creepage distances . 14
6.2.4 Insulation resistance . 16
6.2.5 Dielectric strength . 16
6.2.6 Welding circuit touch current . 18
6.2.7 Liquid cooling . 18
6.3 Protection against electric shock in normal service (direct contact) . 19
6.3.1 General . 19
6.3.2 Rated no-load voltage at the output . 19
6.3.3 Protection provided by barriers or the enclosure . 20
6.3.4 Capacitors . 21
6.3.5 Automatic discharge of input capacitors . 21
6.3.6 Protective conductor current under normal condition. 22
6.3.7 Touch current in normal condition . 22
6.4 Protection against electric shock in case of a fault condition (indirect
contact) . 22
6.4.1 General . 22
6.4.2 Protective provisions for welding circuit . 24
6.4.3 Internal conductors and connections . 36
6.4.4 Touch current in fault condition . 36
6.4.5 DC resistance welding equipment operating at mains frequency . 37
6.4.6 DC resistance welding equipment operating at medium frequency . 37
6.4.7 Continuity of the protective bonding circuit . 37
6.5 Additional user requirements. 38
6.6 Supply voltage . 38
6.7 Conductors of the welding circuit . 38
7 Thermal requirements . 38
7.1 Heating test . 38
7.1.1 Test conditions . 38
7.1.2 Tolerances of the test parameters . 39
7.1.3 Beginning of the heating test . 40
7.1.4 Duration of the test . 40
7.2 Temperature measurement . 40
7.2.1 Measurements conditions . 40
7.2.2 Surface temperature sensor . 40
7.2.3 Resistance . 40
7.2.4 Embedded temperature sensor . 41
7.2.5 Determination of the ambient temperature (t ) . 41
a
7.2.6 Determination of cooling liquid temperature (t ) . 41
a
7.2.7 Recording of temperatures . 41
7.3 Limits of temperature rise . 42
7.3.1 Windings . 42
7.3.2 External surfaces . 42
7.3.3 Other components . 44
7.4 Protection from thermal hazards in normal service (direct contact) . 44
7.4.1 General . 44
7.4.2 Identification of hot surfaces . 44
7.4.3 Protection provided by insulation or other barriers . 45
7.4.4 Protection provided by supplemental cooling . 45
8 Abnormal operation . 45
8.1 General requirements . 45
8.2 Stalled fan test . 45
8.3 Cooling system failure . 45
8.4 Overload test . 46
9 Provisions against mechanical hazards . 46
9.1 General . 46
9.2 Risk analysis. 46
9.2.1 General . 46
9.2.2 Ready-to-use equipment as in delivery state . 46
9.2.3 Equipment not ready to use as in delivery state . 46
9.2.4 Equipment not ready for use and designed to be incorporated in more
complex equipment . 47
9.3 Measures . 47
9.3.1 Minimum measures . 47
9.3.2 Additional measures . 47
9.4 Conformity of components . 48
9.5 Starting for manual operated equipment . 48
10 Instructions and markings . 49
10.1 Instructions . 49
10.2 Markings . 49
10.3 Marking of terminals . 49
Annex A (informative) Nominal voltages of supply networks . 51
Annex B (normative) Construction of supply circuit terminals . 52
B.1 Size of terminals . 52
B.2 Spacings between supply circuit terminals . 52
B.3 Connections at the terminals . 53
B.4 Construction of the terminals . 53
B.5 Fixing of the terminals . 53
Annex C (normative) Touch current measurement in fault condition . 54
Annex D (informative) Extrapolation of temperature to time of shutdown . 56
– 4 – IEC 62135-1:2015 © IEC 2015
Annex E (informative) Example of risk analysis and safety level requirement . 57
E.1 General . 57
E.2 Monitored hazards . 57
E.3 General measures . 57
E.4 Typical hazards by type of equipment . 57
E.4.1 General . 57
E.4.2 Spot welding . 58
E.4.3 Projection welding . 59
E.4.4 Seam welding . 60
E.4.5 Butt welding . 60
Annex F (informative) Indirect contact protection in resistance welding equipment . 61
F.1 Protection against indirect contact by automatic disconnection of the supply . 61
F.1.1 General . 61
F.1.2 TN system . 61
F.1.3 TT systems . 62
F.2 Automatic disconnection of supply in single phase a.c. current equipment . 63
F.2.1 TN system . 63
F.2.2 TT systems . 64
F.3 Automatic disconnection of supply in d.c. current equipment operating at
medium frequency (inverter equipment) . 64
F.3.1 TN system . 64
F.3.2 TT systems . 65
Bibliography . 68
Figure 1 – Measurement of welding circuit touch current . 18
Figure 2 – Measurement of rms values . 19
Figure 3 – Example of metal screen between windings of the supply circuit and the
welding circuit . 26
Figure 4 – Example of protective conductor connected directly to the welding circuit
(single-spot, a.c. current equipment) . 27
Figure 5 – Example of protective conductor connected directly to welding circuits
(multi-spot, a.c. current equipment) . 27
Figure 6 – Example of protective conductor connected directly to welding circuits
(medium-frequency equipment) . 28
Figure 7 – Example of protective conductor connected to welding circuits through
impedances . 29
Figure 8 – Example of protective conductor connected to welding circuits through
auto-inductances . 30
Figure 9 – Example of protective conductor connected to welding circuits through
auto-inductances . 30
Figure 10 – Example of current operated RCD (a.c. current equipment) . 31
Figure 11 – Example of current operated RCD (medium-frequency equipment) . 32
Figure 12 – Example of current operated residual current device and voltage relay . 33
Figure 13 – Example of current operated residual current device and safety-voltage
relay . 34
Figure 14 – Example of safety voltage relay . 35
Figure C.1 – Measuring network for weighted touch current . 54
Figure C.2 – Diagram for touch current measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of class II . 55
Figure C.3 – Diagram for touch current measurement on fault condition for three-
phase four-wire system connection of appliances other than those of class II . 55
Figure E.1 – Structure of a mounted machine . 58
Figure E.2 – Structure of a hand-held welding gun . 58
Figure E.3 – Structure of projection welding machinery . 59
Figure E.4 – Structure of seam welding machinery . 60
Figure E.5 – Structure of butt welding machinery . 60
Figure F.1 – Principle illustration of insulation fault . 61
Figure F.2 – Illustrations of TN systems . 62
Figure F.3 – Illustrations of TT systems . 63
Figure F.4 – Typical fault current . 65
Figure F.5 – Time-to-voltage reference curve . 67
Table 1 – Minimum clearances for overvoltage category III . 13
Table 2 – Minimum creepage distances . 15
Table 3 – Insulation resistance . 16
Table 4 – Dielectric test voltages . 17
Table 5 – Minimum distance through insulation . 25
Table 6 – Continuity of the protective bonding circuit . 37
Table 7 – Limits of temperature rise for windings . 42
Table 8 – Limits of temperature rise for external surfaces of hand-held equipment. 43
Table 9 – Limits of temperature rise for external surfaces of hand-guided equipment . 43
Table 10 – Limits of temperature rise for external surfaces of fixed equipment . 43
Table B.1 – Range of conductor dimensions to be accepted by the supply circuit
terminals . 52
Table B.2 – Spacing between supply circuit terminals . 53
– 6 – IEC 62135-1:2015 © IEC 2015
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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
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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.
This second edition cancels and replaces the first edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– creepage distances for pollution degree 4 are no longer valid (see Table 2);
– insulation requirements for Class II equipment are defined (see Table 3);
– dielectric test voltage interpolation restriction lower limit is changed to 220 V and
interpolation for control and welding circuit is clarified (see Table 4);
– maximum temperature for insulation systems are reviewed in accordance with current
edition of IEC 60085 (see Table 7);
– marking of terminals is defined (see 10.3);
– table for nominal voltages of supply networks is changed adopting Table B.2 of
IEC 60664-1:2007 in place of the Table B.1 values referenced in the previous edition to
provide for equipment to be connected to both earthed and unearthed systems. The
change impacts the creepage and clearance distance requirements for some supply
voltage ratings (see Annex A);
– touch current in fault condition are measurement procedures are clarified (see 6.4.4 and
Annex C).
– welding circuit touch current is defined (see 6.2.6);
– touch current in normal condition are clarified and moved in protection against electric
shock in normal service (see 6.3.7);
– heating test conditions are clarified (see 7.1.1);
– external surface temperature rise limitation is changed (see 7.3.2).
This bilingual version (2016-01) corresponds to the monolingual English version, published in
2015-05.
The text of this standard is based on the following documents:
FDIS Report on voting
26/558/FDIS 26/570/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 stability date indicated on the IEC website 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.
The contents of the corrigendum of February 2016 have been included in this copy.
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 62135-1:2015 © IEC 2015
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 part of IEC 62135 covers stationary and portable equipment.
This part of IEC 62135 specifies electrical safety requirements for design, manufacture and
installation. It does not cover all non-electrical safety requirements (e.g. noise, vibration).
This part of IEC 62135 does not include electromagnetic compatibility (EMC) requirements,
which are included in IEC 62135-2.
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 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 60204-1:2005, 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 60417-DB:2011 , Graphical symbols for use on equipment
IEC 60445, Basic and safety principles for man-machine interface, marking and identification
– Identification of equipment terminals, conductor terminations and conductors
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
___________
“DB” refers to the IEC on-line database.
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
ISO 13849-1, Safety of machinery – Safety-related parts of control systems – Part 1: General
principles for design
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 669, IEC 60664-1
and IEC 60204-1, as well as the following, 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 to entry: It may be a separate unit or part of a complex machine.
Note 2 to entry: 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
[SOURCE: IEC 60050-851:2008, 851-12-05]
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
[SOURCE: IEC 60050-851:2008, 851-12-06]
3.5
welding circuit
conductive material through which the welding current is intended to flow
3.6
control circuit
circuit for the operational control of welding equipment, and/or for protection of the power
circuits
– 10 – IEC 62135-1:2015 © IEC 2015
3.7
conventional value
standardized value that is used as a measure of a parameter for the purposes of comparison,
calibration, testing, etc.
Note 1 to entry: 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
Note 1 to entry: The groups are 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 2 to entry: 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
Note 1 to entry: It is capable of being reset (either manually or automatically) when the temperature falls to the
reset value.
3.16
supply circuit
input 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 to entry: Transients are disregarded.
Note 2 to entry: Both open-circuit conditions and normal operating conditions are taken into account.
4 Environmental conditions
Resistance welding equipment intended for indoor use and complying with this standard shall
be safe to operate when the following environmental conditions prevail:
a) range of ambient air temperature:
during operation: 5 °C to 40 °C;
b) relative humidity of the air:
up to 50 % at 40 °C;
up to 90 % at 20 °C.
c) ambient air, free from abnormal amounts of dust, acids, corrosive gases or substances
etc. other than those generated by the welding process.
d) altitude above sea-level up to 1 000 m;
e) 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.
NOTE Different environmental conditions can be agreed upon between the manufacturer and the purchaser and
the resulting welding equipment is marked accordingly. 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 1 (±1 % 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;
– 12 – IEC 62135-1:2015 © IEC 2015
b) instruments for measuring welding current: class 5;
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.
The requirements for provisions for fault condition protection are given in 6.4.
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.
An equipment designed with insulation based on line-to-neutral 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
a
Voltage impulse voltage impulse voltage
2 3 4 2 3 4
test test
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 0,8 1 500 1 061 0,5 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 60664-1:2007.
NOTE 2 For other pollution degrees and overvoltage categories, see IEC 60664-1.
a
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.
– 14 – IEC 62135-1:2015 © IEC 2015
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).
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 60664-1:2007 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 creep
...
IEC 62135-1 ®
Edition 2.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
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
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IEC 62135-1 ®
Edition 2.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
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
INTERNATIONALE
ICS 25.160 ISBN 978-2-8322-3084-8
– 2 – IEC 62135-1:2015 © IEC 2015
CONTENTS
CONTENTS . 2
FOREWORD . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Environmental conditions . 11
5 Tests . 11
5.1 Test condition . 11
5.2 Measuring instruments . 11
5.3 Type tests . 12
5.4 Routine tests. 12
6 Protection against electric shock . 12
6.1 General . 12
6.2 Insulation . 13
6.2.1 General . 13
6.2.2 Clearances . 13
6.2.3 Creepage distances . 14
6.2.4 Insulation resistance . 16
6.2.5 Dielectric strength . 16
6.2.6 Welding circuit touch current . 18
6.2.7 Liquid cooling . 18
6.3 Protection against electric shock in normal service (direct contact) . 19
6.3.1 General . 19
6.3.2 Rated no-load voltage at the output . 19
6.3.3 Protection provided by barriers or the enclosure . 20
6.3.4 Capacitors . 21
6.3.5 Automatic discharge of input capacitors . 21
6.3.6 Protective conductor current under normal condition. 22
6.3.7 Touch current in normal condition . 22
6.4 Protection against electric shock in case of a fault condition (indirect
contact) . 22
6.4.1 General . 22
6.4.2 Protective provisions for welding circuit . 24
6.4.3 Internal conductors and connections . 36
6.4.4 Touch current in fault condition . 36
6.4.5 DC resistance welding equipment operating at mains frequency . 37
6.4.6 DC resistance welding equipment operating at medium frequency . 37
6.4.7 Continuity of the protective bonding circuit . 37
6.5 Additional user requirements. 38
6.6 Supply voltage . 38
6.7 Conductors of the welding circuit . 38
7 Thermal requirements . 38
7.1 Heating test . 38
7.1.1 Test conditions . 38
7.1.2 Tolerances of the test parameters . 39
7.1.3 Beginning of the heating test . 40
7.1.4 Duration of the test . 40
7.2 Temperature measurement . 40
7.2.1 Measurements conditions . 40
7.2.2 Surface temperature sensor . 40
7.2.3 Resistance . 40
7.2.4 Embedded temperature sensor . 41
7.2.5 Determination of the ambient temperature (t ) . 41
a
7.2.6 Determination of cooling liquid temperature (t ) . 41
a
7.2.7 Recording of temperatures . 41
7.3 Limits of temperature rise . 42
7.3.1 Windings . 42
7.3.2 External surfaces . 42
7.3.3 Other components . 44
7.4 Protection from thermal hazards in normal service (direct contact) . 44
7.4.1 General . 44
7.4.2 Identification of hot surfaces . 44
7.4.3 Protection provided by insulation or other barriers . 45
7.4.4 Protection provided by supplemental cooling . 45
8 Abnormal operation . 45
8.1 General requirements . 45
8.2 Stalled fan test . 45
8.3 Cooling system failure . 45
8.4 Overload test . 46
9 Provisions against mechanical hazards . 46
9.1 General . 46
9.2 Risk analysis. 46
9.2.1 General . 46
9.2.2 Ready-to-use equipment as in delivery state . 46
9.2.3 Equipment not ready to use as in delivery state . 46
9.2.4 Equipment not ready for use and designed to be incorporated in more
complex equipment . 47
9.3 Measures . 47
9.3.1 Minimum measures . 47
9.3.2 Additional measures . 47
9.4 Conformity of components . 48
9.5 Starting for manual operated equipment . 48
10 Instructions and markings . 49
10.1 Instructions . 49
10.2 Markings . 49
10.3 Marking of terminals . 49
Annex A (informative) Nominal voltages of supply networks . 51
Annex B (normative) Construction of supply circuit terminals . 52
B.1 Size of terminals . 52
B.2 Spacings between supply circuit terminals . 52
B.3 Connections at the terminals . 53
B.4 Construction of the terminals . 53
B.5 Fixing of the terminals . 53
Annex C (normative) Touch current measurement in fault condition . 54
– 4 – IEC 62135-1:2015 © IEC 2015
Annex D (informative) Extrapolation of temperature to time of shutdown . 56
Annex E (informative) Example of risk analysis and safety level requirement . 57
E.1 General . 57
E.2 Monitored hazards . 57
E.3 General measures . 57
E.4 Typical hazards by type of equipment . 57
E.4.1 General . 57
E.4.2 Spot welding . 58
E.4.3 Projection welding . 59
E.4.4 Seam welding . 60
E.4.5 Butt welding . 60
Annex F (informative) Indirect contact protection in resistance welding equipment . 61
F.1 Protection against indirect contact by automatic disconnection of the supply . 61
F.1.1 General . 61
F.1.2 TN system . 61
F.1.3 TT systems . 62
F.2 Automatic disconnection of supply in single phase a.c. current equipment . 63
F.2.1 TN system . 63
F.2.2 TT systems . 64
F.3 Automatic disconnection of supply in d.c. current equipment operating at
medium frequency (inverter equipment) . 64
F.3.1 TN system . 64
F.3.2 TT systems . 65
Bibliography . 68
Figure 1 – Measurement of welding circuit touch current . 18
Figure 2 – Measurement of rms values . 19
Figure 3 – Example of metal screen between windings of the supply circuit and the
welding circuit . 26
Figure 4 – Example of protective conductor connected directly to the welding circuit
(single-spot, a.c. current equipment) . 27
Figure 5 – Example of protective conductor connected directly to welding circuits
(multi-spot, a.c. current equipment) . 27
Figure 6 – Example of protective conductor connected directly to welding circuits
(medium-frequency equipment) . 28
Figure 7 – Example of protective conductor connected to welding circuits through
impedances . 29
Figure 8 – Example of protective conductor connected to welding circuits through
auto-inductances . 30
Figure 9 – Example of protective conductor connected to welding circuits through
auto-inductances . 30
Figure 10 – Example of current operated RCD (a.c. current equipment) . 31
Figure 11 – Example of current operated RCD (medium-frequency equipment) . 32
Figure 12 – Example of current operated residual current device and voltage relay . 33
Figure 13 – Example of current operated residual current device and safety-voltage
relay . 34
Figure 14 – Example of safety voltage relay . 35
Figure C.1 – Measuring network for weighted touch current . 54
Figure C.2 – Diagram for touch current measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of class II . 55
Figure C.3 – Diagram for touch current measurement on fault condition for three-
phase four-wire system connection of appliances other than those of class II . 55
Figure E.1 – Structure of a mounted machine . 58
Figure E.2 – Structure of a hand-held welding gun . 58
Figure E.3 – Structure of projection welding machinery . 59
Figure E.4 – Structure of seam welding machinery . 60
Figure E.5 – Structure of butt welding machinery . 60
Figure F.1 – Principle illustration of insulation fault . 61
Figure F.2 – Illustrations of TN systems . 62
Figure F.3 – Illustrations of TT systems . 63
Figure F.4 – Typical fault current . 65
Figure F.5 – Time-to-voltage reference curve . 67
Table 1 – Minimum clearances for overvoltage category III . 13
Table 2 – Minimum creepage distances . 15
Table 3 – Insulation resistance . 16
Table 4 – Dielectric test voltages . 17
Table 5 – Minimum distance through insulation . 25
Table 6 – Continuity of the protective bonding circuit . 37
Table 7 – Limits of temperature rise for windings . 42
Table 8 – Limits of temperature rise for external surfaces of hand-held equipment. 43
Table 9 – Limits of temperature rise for external surfaces of hand-guided equipment . 43
Table 10 – Limits of temperature rise for external surfaces of fixed equipment . 43
Table B.1 – Range of conductor dimensions to be accepted by the supply circuit
terminals . 52
Table B.2 – Spacing between supply circuit terminals . 53
– 6 – IEC 62135-1:2015 © IEC 2015
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
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agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
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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.
This second edition cancels and replaces the first edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– creepage distances for pollution degree 4 are no longer valid (see Table 2);
– insulation requirements for Class II equipment are defined (see Table 3);
– dielectric test voltage interpolation restriction lower limit is changed to 220 V and
interpolation for control and welding circuit is clarified (see Table 4);
– maximum temperature for insulation systems are reviewed in accordance with current
edition of IEC 60085 (see Table 7);
– marking of terminals is defined (see 10.3);
– table for nominal voltages of supply networks is changed adopting Table B.2 of
IEC 60664-1:2007 in place of the Table B.1 values referenced in the previous edition to
provide for equipment to be connected to both earthed and unearthed systems. The
change impacts the creepage and clearance distance requirements for some supply
voltage ratings (see Annex A);
– touch current in fault condition are measurement procedures are clarified (see 6.4.4 and
Annex C).
– welding circuit touch current is defined (see 6.2.6);
– touch current in normal condition are clarified and moved in protection against electric
shock in normal service (see 6.3.7);
– heating test conditions are clarified (see 7.1.1);
– external surface temperature rise limitation is changed (see 7.3.2).
This bilingual version (2016-01) corresponds to the monolingual English version, published in
2015-05.
The text of this standard is based on the following documents:
FDIS Report on voting
26/558/FDIS 26/570/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 stability date indicated on the IEC website 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.
The contents of the corrigendum of February 2016 have been included in this copy.
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 62135-1:2015 © IEC 2015
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 part of IEC 62135 covers stationary and portable equipment.
This part of IEC 62135 specifies electrical safety requirements for design, manufacture and
installation. It does not cover all non-electrical safety requirements (e.g. noise, vibration).
This part of IEC 62135 does not include electromagnetic compatibility (EMC) requirements,
which are included in IEC 62135-2.
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 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 60204-1:2005, 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 60417-DB:2011 , Graphical symbols for use on equipment
IEC 60445, Basic and safety principles for man-machine interface, marking and identification
– Identification of equipment terminals, conductor terminations and conductors
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
___________
“DB” refers to the IEC on-line database.
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
ISO 13849-1, Safety of machinery – Safety-related parts of control systems – Part 1: General
principles for design
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 669, IEC 60664-1
and IEC 60204-1, as well as the following, 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 to entry: It may be a separate unit or part of a complex machine.
Note 2 to entry: 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
[SOURCE: IEC 60050-851:2008, 851-12-05]
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
[SOURCE: IEC 60050-851:2008, 851-12-06]
3.5
welding circuit
conductive material through which the welding current is intended to flow
3.6
control circuit
circuit for the operational control of welding equipment, and/or for protection of the power
circuits
– 10 – IEC 62135-1:2015 © IEC 2015
3.7
conventional value
standardized value that is used as a measure of a parameter for the purposes of comparison,
calibration, testing, etc.
Note 1 to entry: 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
Note 1 to entry: The groups are 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 2 to entry: 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
Note 1 to entry: It is capable of being reset (either manually or automatically) when the temperature falls to the
reset value.
3.16
supply circuit
input 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 to entry: Transients are disregarded.
Note 2 to entry: Both open-circuit conditions and normal operating conditions are taken into account.
4 Environmental conditions
Resistance welding equipment intended for indoor use and complying with this standard shall
be safe to operate when the following environmental conditions prevail:
a) range of ambient air temperature:
during operation: 5 °C to 40 °C;
b) relative humidity of the air:
up to 50 % at 40 °C;
up to 90 % at 20 °C.
c) ambient air, free from abnormal amounts of dust, acids, corrosive gases or substances
etc. other than those generated by the welding process.
d) altitude above sea-level up to 1 000 m;
e) 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.
NOTE Different environmental conditions can be agreed upon between the manufacturer and the purchaser and
the resulting welding equipment is marked accordingly. 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 1 (±1 % 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;
– 12 – IEC 62135-1:2015 © IEC 2015
b) instruments for measuring welding current: class 5;
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.
The requirements for provisions for fault condition protection are given in 6.4.
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.
An equipment designed with insulation based on line-to-neutral 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 overvolt
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