IEC 60974-1:2021
(Main)Arc welding equipment - Part 1: Welding power sources
Arc welding equipment - Part 1: Welding power sources
IEC 60974-1:2021 is applicable to power sources for arc welding and allied processes designed for industrial and professional use, and supplied by a voltage not exceeding 1 000 V, battery supplied or driven by mechanical means. This document specifies safety and performance requirements of welding power sources and plasma cutting systems. This sixth edition cancels and replaces the fifth edition published in 2017 and Amendment 1:2019. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- Table 1 with an alphabetical cross-reference listing of terms added;
- clearance and creepage distance reference document changed to IEC 60664-1:2020;
- 6.1.2 and 6.1.3 modified to follow IEC 60664-1 basic insulation dimensioning for mains supply with rationalized voltages;
- abnormal capacitor test of 6.2.2 moved to new Subclause 9.5;
- 6.2.5 and 6.3.6 modified to use touch current measuring network weighted for letgo-immobilization and supply voltage tolerance requirement added;
- 16.3 new structure and accuracy requirement for displayed voltage value ;
- Annex A changed to normative and Table A.2 and Table A.3 added;
- Annex L editorial update to standardized symbols;
- redraft of efficiency and idle state power measurement in Annex M based on IEC 62301:2011;
- Annex N measurement network weighted for letgo-immobilization added.
Matériel de soudage à l'arc - Partie 1: Sources de courant de soudage
L’IEC 60974-1:2021 s'applique aux sources de courant de soudage à l'arc et aux procédés connexes conçus pour un usage industriel et professionnel qui sont alimentés sous une tension ne dépassant pas 1 000 V, alimentés par batterie ou entraînés par des moyens mécaniques. Le présent document spécifie les exigences de sécurité et de fonctionnement des sources de courant de soudage et des systèmes de coupage par plasma. Cette sixième édition annule et remplace la cinquième édition parue en 2017 et l'Amendement 1:2019. Elle constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente.
- Ajout du Tableau 1 avec la liste des termes par référence croisée dans l’ordre alphabétique de la langue source.
- Le document de référence des distances d’isolement dans l’air et des lignes de fuite devient IEC 60664-1:2020.
- Modification du 6.1.2 et du 6.1.3 afin de respecter le dimensionnement de l’isolation principale spécifié dans l’IEC 60664-1 pour le réseau d’alimentation avec des tensions rationalisées.
- Déplacement de l’essai de condensateur anormal du 6.2.2 au nouveau 9.5.
- Modification du 6.2.5 du 6.3.6 afin d’utiliser le réseau de mesure du courant de contact pondéré pour une opération de non-lâcher/immobilisation et ajout d’une exigence de tolérance pour la tension d’alimentation.
- Nouvelle structure du 16.3 et nouvelle exigence d’exactitude pour la valeur de tension affichée.
- Modification de l’Annexe A qui devient une annexe normative et ajout du Tableau A.2 et du Tableau A.3.
- Mise à jour rédactionnelle de l’Annexe L pour l'utilisation des symboles normalises.
- Nouvelle rédaction du mesurage du rendement et de la puissance en état au ralenti (Annexe M sur la base de l’IEC 62301:2011).
- Ajout d’un réseau de mesure pondéré pour une opération de non-lâcher/immobilisation (Annexe N).
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Standards Content (Sample)
IEC 60974-1 ®
Edition 6.0 2021-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Arc welding equipment –
Part 1: Welding power sources
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IEC 60974-1 ®
Edition 6.0 2021-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Arc welding equipment –
Part 1: Welding power sources
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.160.30 ISBN 978-2-8322-9962-3
– 2 – IEC 60974-1:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 7
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
3.1 General terms and definitions . 13
3.2 Terms and definitions related to BATTERY SYSTEMs . 22
3.3 Terms and definitions related to efficiency and IDLE STATE power
measurement . 24
4 Environmental conditions . 26
5 Tests . 26
5.1 Test conditions . 26
5.2 Measuring instruments . 26
5.3 Conformity of components . 27
5.4 TYPE TESTs . 27
5.5 ROUTINE TESTs . 29
6 Protection against electric shock . 29
6.1 Insulation . 29
6.2 Protection against electric shock in normal service (direct contact) . 36
6.3 Protection against electric shock in case of a fault condition (indirect contact) . 39
7 Thermal requirements . 41
7.1 Heating test . 41
7.2 Temperature measurement . 42
7.3 Limits of TEMPERATURE RISE . 44
7.4 Loading test . 45
7.5 Commutators and slip-rings . 46
8 THERMAL PROTECTION . 46
8.1 General requirements . 46
8.2 Construction . 46
8.3 Location . 46
8.4 Operating capacity . 47
8.5 Operation . 47
8.6 Resetting . 47
8.7 Indication . 47
9 Abnormal operation . 47
9.1 General requirements . 47
9.2 Stalled fan test . 48
9.3 Short circuit test . 48
9.4 Overload test . 49
9.5 Capacitors short circuit . 49
10 Connection to the supply network . 49
10.1 Supply voltage . 49
10.2 Multi-supply voltage . 50
10.3 Means of connection to the SUPPLY CIRCUIT . 50
10.4 Marking of terminals . 50
10.5 PROTECTIVE CIRCUIT . 51
10.6 Cable anchorage . 52
10.7 Inlet openings . 53
10.8 SUPPLY CIRCUIT on/off switching device . 53
10.9 Supply cables . 54
10.10 Supply coupling device (attachment plug) . 55
11 Output . 55
11.1 RATED NO-LOAD VOLTAGE . 55
11.2 TYPE TEST values of the CONVENTIONAL LOAD VOLTAGE . 58
11.3 Mechanical switching devices used to adjust output . 59
11.4 WELDING CIRCUIT connections . 60
11.5 Power supply to external devices connected to the WELDING CIRCUIT . 61
11.6 Auxiliary power supply . 61
11.7 Welding cables . 61
12 CONTROL CIRCUITs . 62
12.1 General requirement . 62
12.2 Isolation of CONTROL CIRCUITs . 62
12.3 WORKING VOLTAGEs of remote CONTROL CIRCUITs . 62
13 HAZARD REDUCING DEVICE . 62
13.1 General requirements . 62
13.2 Types of HAZARD REDUCING DEVICES . 63
13.3 Requirements for HAZARD REDUCING DEVICEs . 63
14 Mechanical provisions . 64
14.1 General requirements . 64
14.2 Enclosure . 64
14.3 Handling means . 65
14.4 Drop withstand . 65
14.5 Tilting stability . 66
15 RATING PLATE . 66
15.1 General requirements . 66
15.2 Description . 66
15.3 Contents . 67
15.4 Tolerances . 70
15.5 Direction of rotation . 71
16 Adjustment of the output . 71
16.1 Type of adjustment . 71
16.2 Marking of the adjusting device . 71
16.3 Indication of current or voltage control . 72
17 Instructions and markings . 72
17.1 Instructions . 72
17.2 Markings . 73
Annex A (informative normative) Nominal voltages of supply networks . 74
Annex B (informative) Example of a combined dielectric test . 77
Annex C (normative) Unbalanced load in case of AC tungsten inert-gas WELDING
POWER SOURCES . 78
C.1 General . 78
C.2 Unbalanced load . 79
C.3 Example for an unbalanced load . 79
Annex D (informative) Extrapolation of temperature to time of shutdown . 81
– 4 – IEC 60974-1:2021 RLV © IEC 2021
Annex E (normative) Construction of SUPPLY CIRCUIT terminals . 82
E.1 Size of terminals . 82
E.2 Connections at the terminals . 82
E.3 Construction of the terminals . 83
E.4 Fixing of the terminals . 83
Annex F (informative) Cross-reference to non-SI units . 84
Annex G (informative) Suitability of supply network for the measurement of the true
RMS value of the supply current . 85
Annex H (informative) Plotting of STATIC CHARACTERISTICS . 86
H.1 General . 86
H.2 Method . 86
H.3 Analysis of the results . 86
Annex I (normative) Test methods for a 10 Nm impact . 87
I.1 Pendulum impact hammer . 87
I.2 Free fall spherical steel weight . 87
Annex J (normative) Thickness of sheet metal for enclosures . 89
Annex K (informative) Examples of RATING PLATES . 91
Annex L (informative) Graphical symbols for arc welding equipment . 98
L.1 General . 98
L.2 Use of symbols . 98
L.3 Symbols . 99
L.4 Examples of combinations of symbols . 117
L.5 Examples of control panels . 119
Annex M (informative) Efficiency and IDLE STATE power measurement . 122
M.1 Measuring efficiency .
M.2 Measuring idle state power .
M.1 General conditions for measurement . 123
M.2 Measurements . 124
M.3 Test report . 127
M.4 Test report template . 129
Annex N (normative) TOUCH CURRENT measurement in fault condition . 131
Annex O (normative) Battery-powered WELDING POWER SOURCES . 137
O.1 General . 137
O.4 Environmental conditions . 138
O.5 Tests . 138
O.6 Protection against electric shock . 140
O.7 Thermal requirements . 142
O.8 THERMAL PROTECTION . 144
O.9 Abnormal operation . 144
O.10 Connection to the supply network . 148
O.14 Mechanical provisions . 150
O.15 RATING PLATE . 151
O.17 Instructions and markings . 153
Annex P (normative) Conformity of components .
Bibliography . 157
Figure 1 – Flow chart for conformity methods of 5.3 . 28
Figure 2 – Example of insulation configuration for CLASS I EQUIPMENT . 30
Figure 3 – Measurement of WELDING CIRCUIT TOUCH CURRENT . 38
Figure 4 – Measurement of TOUCH CURRENT in normal condition . 38
Figure 5 – Measurement of RMS values . 57
Figure 6 – Measurement of peak values . 58
Figure 7 – Principle of the RATING PLATE . 67
Figure B.1 – Combined high-voltage transformers . 77
Figure C.1 – Voltage and current during AC tungsten inert-gas welding . 78
Figure C.2 – Unbalanced voltage during AC tungsten inert-gas welding . 79
Figure C.3 – AC WELDING POWER SOURCE with unbalanced load . 80
Figure I.1 – Test set-up . 87
Figure K.1 – Single-phase transformer . 91
Figure K.2 – Three-phase rotating frequency converter . 92
Figure K.3 – Subdivided RATING PLATE: single-/three-phase transformer rectifier . 93
Figure K.4 – Engine-generator-rectifier . 94
Figure K.5 – Single-/three-phase inverter type . 95
Figure K.6 – Battery-powered WELDING POWER SOURCE with INTEGRAL BATTERY . 96
Figure K.7 – Battery-powered WELDING POWER SOURCE with detachable / separable
BATTERY . 97
Figure L.1 – Input voltage power switch . 119
Figure L.2 – Arc force control potentiometer . 119
Figure L.3 – Remote receptacle and selector switches . 119
Figure L.4 – Terminals with inductance selector for MIG/MAG welding. 120
Figure L.5 – Process switch (MMA, TIG, MIG) . 120
Figure L.6 – Selector switch on AC/DC equipment . 120
Figure L.7 – Panel indicator lights (overheat, fault, arc striking, output voltage) . 120
Figure L.8 – Setting pulsing parameters using digital display . 121
Figure M.1 – Measurement procedure . 127
Figure N.1 – Measuring network for weighted touch current, TOUCH CURRENT weighted
for perception or startle-reaction . 131
Figure N.2 – Measuring network, TOUCH CURRENT weighted for letgo-immobilization . 132
Figure N.3 – Diagram for TOUCH CURRENT measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of CLASS II . 134
Figure N.4 – Diagram for TOUCH CURRENT measurement on fault condition for three-
phase four-wire system connection of appliances other than those of CLASS II . 136
Figure O.1 – Marking of BATTERY VOLTAGE CLASS B electric components . 154
Figure P.1 – Flow chart for conformity methods of Annex P .
Table 1 – Alphabetical list of terms . 11
Table 2 – Minimum CLEARANCES for overvoltage category III . 30
Table 3 – Minimum CREEPAGE DISTANCES . 33
Table 4 – Insulation resistance . 34
Table 5 – Dielectric test voltages . 35
Table 6 – Minimum distance through insulation . 39
– 6 – IEC 60974-1:2021 RLV © IEC 2021
Table 7 – Temperature limits for windings, commutators and slip-rings . 44
Table 8 – Temperature limits for external surfaces . 45
Table 9 – Cross-section of the output short-circuit conductor . 48
Table 10 – Current and time requirements for PROTECTIVE CIRCUITS . 51
Table 11 – Minimum cross-sectional area of the external protective copper conductor . 52
Table 12 – Verification of continuity of the PROTECTIVE CIRCUIT . 52
Table 13 – Pull. 53
Table 14 – Summary of allowable RATED NO-LOAD VOLTAGES . 57
Table 15 – HAZARD REDUCING DEVICE requirements . 63
Table A.1 – Nominal voltages for supply networks with protective overvoltage control . 74
Table A.2 – Single-phase three-wire or two-wire AC or DC systems . 75
Table A.3 – Three-phase four-wire or three-wire AC systems . 76
Table E.1 – Range of conductor dimensions to be accepted by the SUPPLY CIRCUIT
terminals . 82
Table F.1 – Cross-reference for mm to American wire gauge (AWG) . 84
Table I.1 – Angle of rotation θ to obtain 10 Nm impact . 87
Table I.2 – Mass of the free fall weight and height of the free fall . 88
Table J.1 – Minimum thickness of sheet metal for steel enclosures . 89
Table J.2 – Minimum thickness of sheet metal for enclosures of aluminium, brass or
copper . 90
Table L.1 – Letters used as symbols . 99
Table M.1 – Typical nominal electricity supply details for some regions . 123
Table M.2 – Load conditions for the ARC WELDING POWER SOURCE . 125
Table M.3 – Required reported data (measured and calculated). 128
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ARC WELDING EQUIPMENT –
Part 1: Welding power sources
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60974-1:2017+AMD1:2019 CSV. A vertical bar appears
in the margin wherever a change has been made. Additions are in green text, deletions
are in strikethrough red text.
– 8 – IEC 60974-1:2021 RLV © IEC 2021
IEC 60974-1 has been prepared by IEC technical committee 26: Electric welding. It is an
International Standard.
This sixth edition cancels and replaces the fifth edition published in 2017 and
Amendment 1:2019. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Table 1 with an alphabetical cross-reference listing of terms added;
b) CLEARANCE and CREEPAGE DISTANCE reference document changed to IEC 60664-1:2020;
c) 6.1.2 and 6.1.3 modified to follow IEC 60664-1 BASIC INSULATION dimensioning for mains
supply with rationalized voltages;
d) abnormal capacitor test of 6.2.2 moved to new Subclause 9.5;
TOUCH CURRENT measuring network weighted for letgo-
e) 6.2.5 and 6.3.6 modified to use
immobilization and supply voltage tolerance requirement added;
f) 16.3 new structure and accuracy requirement for displayed voltage value ;
g) Annex A changed to normative and Table A.2 and Table A.3 added;
h) Annex L editorial update to standardized symbols;
i) redraft of efficiency and IDLE STATE power measurement in Annex M based on
IEC 62301:2011;
j) Annex N measurement network weighted for letgo-immobilization added.
The text of this International Standard is based on the following documents:
FDIS Report on voting
26/724/FDIS 26/727/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
In this document, the following print types are used:
– conformity statements: in italic type.
– terms used throughout this document which have been defined in Clause 3: in bold type
SMALL ROMAN CAPITALS.
A list of all parts of the IEC 60974 series can be found, under the general title Arc welding
equipment, on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
– 10 – IEC 60974-1:2021 RLV © IEC 2021
ARC WELDING EQUIPMENT –
Part 1: Welding power sources
1 Scope
This part of IEC 60974 is applicable to power sources for arc welding and allied processes
designed for INDUSTRIAL AND PROFESSIONAL USE, and supplied by a voltage not exceeding
1 000 V, BATTERY supplied or driven by mechanical means.
This document specifies safety and performance requirements of WELDING POWER SOURCES and
PLASMA CUTTING SYSTEMS.
This document is not applicable to limited duty arc welding and cutting power sources which
are designed mainly for use by laymen and designed in accordance with IEC 60974-6.
This document includes requirements for battery-powered WELDING POWER SOURCES and
BATTERY packs, which are given in Annex O.
This document is not applicable to testing of power sources during periodic maintenance or
after repair.
NOTE 1 Typical allied processes are electric arc cutting and arc spraying.
NOTE 2 AC systems having a nominal voltage between 100 V and 1 000 V are given in Table 1 of IEC 60038:2009.
NOTE 3 This document does not include electromagnetic compatibility (EMC) requirements.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
IEC 60050-151, International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and
magnetic devices (available at: http://www.electropedia.org)
IEC 60050-851, International Electrotechnical Vocabulary (IEV) – Part 851: Electric welding
(available at: http://www.electropedia.org)
IEC 60245-6, Rubber insulated cables – Rated voltages up to and including 450/750 V – Part 6:
Arc welding electrode cables
IEC 60417, Graphical symbols for use on equipment (available at: http://www.graphical-
symbols.info/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 60664-1:20072020, 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 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
IEC 60974-7, Arc welding equipment – Part 7: Torches
IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC)
requirements
IEC 61140, Protection against electric shock – Common aspects for installation and equipment
IEC 61558-2-4, Safety of transformers, reactors, power supply units and similar products for
supply voltages up to 1 100 V – Part 2-4: Particular requirements and tests for isolating
transformers and power supply units incorporating isolating transformers
IEC 61558-2-6, Safety of transformers, reactors, power supply units and similar products for
supply voltages up to 1 100 V – Part 2-6: Particular requirements and tests for safety isolating
transformers and power supply units incorporating safety isolating transformers
IEC 62133-1:— 2017, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for portable sealed secondary cells, and for batteries made
from them, for use in portable applications – Part 1: Nickel systems
IEC 62133-2:— 2017, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for portable sealed secondary lithium cells, and for batteries
made from them, for use in portable applications – Part 2: Lithium systems
IEC 62301:2011, Household electrical appliances – Measurement of standby power
ISO 7010:20112019, Graphical symbols – Safety colours and safety signs – Registered safety
signs
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-151,
IEC 60050-851, IEC 60664-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
Table 1 provides an alphabetical cross-reference listing of terms.
__________
Under preparation. Stage at the time of publication: IEC CDV 62133-1:2015.
Under preparation. Stage at the time of publication: IEC CDV 62133-2:2015.
– 12 – IEC 60974-1:2021 RLV © IEC 2021
Table 1 – Alphabetical list of terms
Term Term Term Term Term Term
number number number
active power 3.3.3 explosion 3.2.23 rated reduced no-load 3.1.27
voltage
apparent power 3.3.4 fixed installation 3.1.62 rated supply current 3.1.30
basic insulation 3.1.50 flat characteristic 3.1.9 rated supply 3.3.1
frequency
basic protection 3.2.18 fully charged cell 3.2.10 rated supply voltage 3.1.29
battery 3.2.1 fully discharged cell 3.2.11 rated switched no- 3.1.28
load voltage
battery system 3.2.5 functional insulation 3.1.65 rated value 3.1.21
battery voltage class 3.2.19 general purpose 3.2.12 rating plate 3.1.22
A batteries
battery voltage class 3.2.20 hazard reducing 3.1.47 reinforced insulation 3.1.53
B device
C rate 3.2.6 idle state 3.1.66 remote control 3.1.60
cell 3.2.7 industrial and 3.1.2 routine test 3.1.6
professional use
charger 3.2.8 instructed person 3.1.4 safety extra-low 3.1.56
voltage
charging system 3.2.9 integral battery 3.2.2 separable battery 3.2.4
pack
charring 3.2.21 load voltage 3.1.14 single-fault condition 3.1.61
class I equipment 3.1.48 material group 3.1.42 specified operating 3.2.14
region
class II equipment 3.1.49 maximum charging 3.2.13 specified operating 3.2.14.1
current region for charging
class of insulation 3.1.64 maximum effective 3.1.33 static characteristic 3.1.10
supply current
clearance 3.1.38 micro-environment 3.1.41 supplementary 3.1.51
insulation
consecutive operating 3.2.22 no-load voltage 3.1.15 supply circuit 3.1.57
cycle
control circuit 3.1.12 plasma cutting power 3.1.55 temperature rise 3.1.43
source
conventional load 3.1.18 plasma cutting 3.1.54 thermal equilibrium 3.1.44
system
conventional load 3.1.20 pollution degree 3.1.40 thermal protection 3.1.45
voltage
conventional value 3.1.16 power factor 3.3.5 total harmonic 3.3.6
distortion
conventional welding 3.1.17 protective circuit 3.1.63 touch current 3.1.59
condition
conventional welding 3.1.19 rated idle speed 3.1.36 type test 3.1.5
current
creepage distance 3.1.39 rated load speed 3.1.34 upper limit charging 3.2.15
voltage
detachable battery 3.2.3 rated maximum 3.1.32 venting 3.2.16
pack supply current
double insulation 3.1.52 rated maximum 3.1.24 visual inspection 3.1.7
welding current
drooping 3.1.8 rated minimum 3.1.25 welding circuit 3.1.11
characteristic welding current
Term Term Term Term Term Term
number number number
duty cycle 3.1.37 rated no-load speed 3.1.35 welding current 3.1.13
electronic component 3.2.17 rated no-load supply 3.1.31 welding power source 3.1.1
current
environment with 3.1.46 rated no-load voltage 3.1.26 welding power source 3.3.2
increased risk of efficiency
electric shock
expert 3.1.3 rated output 3.1.23 working voltage 3.1.58
3.1 General terms and definitions
3.1.1
welding power source
arc welding power source
equipment for supplying current and voltage and having the required characteristics suitable for
arc welding and allied processes
Note 1 to entry: A WELDING POWER SOURCE can also supply services to other equipment and auxiliaries for example
auxiliary power, cooling liquid, consumable arc welding electrode and gas to shield the arc and the welding area.
Note 2 to entry: This entry revises IEC 60050-851:2008, 851-13-01, which will be updated.
3.1.2
industrial and professional use
use intended only for EXPERTS or INSTRUCTED PERSONS
[SOURCE: IEC 60050-851:2008, 851-11-12]
3.1.3
expert
competent person
skilled person
person who can judge the work assigned and recognize possible hazards on the basis of
professional training, knowledge, experience and knowledge of the relevant equipment
Note 1 to entry: Several years of practice in the relevant technical field can be taken into consideration in
assessment of professional training.
[SOURCE: IEC 60050-851:2008, 851-11-10]
3.1.4
instructed person
person informed about the tasks assigned and about the possible hazards involved in neglectful
behaviour
Note 1 to entry: If necessary, the person has undergone some training.
[SOURCE: IEC 60050-851:2008, 851-11-13]
3.1.5
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]
– 14 – IEC 60974-1:2021 RLV © IEC 2021
3.1.6
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]
3.1.7
visual inspection
inspection by eye to verify that there are no apparent discrepancies with respect to provisions
of the standard concerned
[SOURCE: IEC 60050-851:2008, 851-11-11]
3.1.8
...
IEC 60974-1 ®
Edition 6.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Arc welding equipment –
Part 1: Welding power sources
Matériel de soudage à l’arc –
Partie 1: Sources de courant de soudage
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IEC 60974-1 ®
Edition 6.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Arc welding equipment –
Part 1: Welding power sources
Matériel de soudage à l’arc –
Partie 1: Sources de courant de soudage
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.160.30 ISBN 978-2-8322-9914-2
– 2 – IEC 60974-1:2021 © IEC 2021
CONTENTS
FOREWORD . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
3.1 General terms and definitions . 12
3.2 Terms and definitions related to BATTERY SYSTEMs . 21
3.3 Terms and definitions related to efficiency and IDLE STATE power
measurement . 23
4 Environmental conditions . 25
5 Tests . 25
5.1 Test conditions . 25
5.2 Measuring instruments . 25
5.3 Conformity of components . 26
5.4 TYPE TESTs . 27
5.5 ROUTINE TESTs . 27
6 Protection against electric shock . 28
6.1 Insulation . 28
6.2 Protection against electric shock in normal service (direct contact) . 35
6.3 Protection against electric shock in case of a fault condition (indirect contact) . 38
7 Thermal requirements . 40
7.1 Heating test . 40
7.2 Temperature measurement . 41
7.3 Limits of TEMPERATURE RISE . 43
7.4 Loading test . 44
7.5 Commutators and slip-rings . 45
8 THERMAL PROTECTION . 45
8.1 General requirements . 45
8.2 Construction . 45
8.3 Location . 45
8.4 Operating capacity . 46
8.5 Operation . 46
8.6 Resetting . 46
8.7 Indication . 46
9 Abnormal operation . 46
9.1 General requirements . 46
9.2 Stalled fan test . 47
9.3 Short circuit test . 47
9.4 Overload test . 48
9.5 Capacitors short circuit . 48
10 Connection to the supply network . 48
10.1 Supply voltage . 48
10.2 Multi-supply voltage . 49
10.3 Means of connection to the SUPPLY CIRCUIT . 49
10.4 Marking of terminals . 49
10.5 PROTECTIVE CIRCUIT . 50
10.6 Cable anchorage . 51
10.7 Inlet openings . 52
10.8 SUPPLY CIRCUIT on/off switching device . 52
10.9 Supply cables . 53
10.10 Supply coupling device (attachment plug) . 54
11 Output . 54
11.1 RATED NO-LOAD VOLTAGE . 54
11.2 TYPE TEST values of the CONVENTIONAL LOAD VOLTAGE . 57
11.3 Mechanical switching devices used to adjust output . 58
11.4 WELDING CIRCUIT connections . 59
11.5 Power supply to external devices connected to the WELDING CIRCUIT . 60
11.6 Auxiliary power supply . 60
11.7 Welding cables . 60
12 CONTROL CIRCUITs . 61
12.1 General requirement . 61
12.2 Isolation of CONTROL CIRCUITs . 61
12.3 WORKING VOLTAGEs of remote CONTROL CIRCUITs . 61
13 HAZARD REDUCING DEVICE . 61
13.1 General requirements . 61
13.2 Types of HAZARD REDUCING DEVICES . 62
13.3 Requirements for HAZARD REDUCING DEVICEs . 62
14 Mechanical provisions . 63
14.1 General requirements . 63
14.2 Enclosure . 63
14.3 Handling means . 64
14.4 Drop withstand . 64
14.5 Tilting stability . 65
15 RATING PLATE . 65
15.1 General requirements . 65
15.2 Description . 65
15.3 Contents . 66
15.4 Tolerances . 69
15.5 Direction of rotation . 70
16 Adjustment of the output . 70
16.1 Type of adjustment . 70
16.2 Marking of the adjusting device . 70
16.3 Indication of current or voltage control . 71
17 Instructions and markings . 71
17.1 Instructions . 71
17.2 Markings . 72
Annex A (normative) Nominal voltages of supply networks . 73
Annex B (informative) Example of a combined dielectric test . 76
Annex C (normative) Unbalanced load in case of AC tungsten inert-gas WELDING
POWER SOURCES . 77
C.1 General . 77
C.2 Unbalanced load . 78
C.3 Example for an unbalanced load . 78
Annex D (informative) Extrapolation of temperature to time of shutdown . 80
– 4 – IEC 60974-1:2021 © IEC 2021
Annex E (normative) Construction of SUPPLY CIRCUIT terminals . 81
E.1 Size of terminals . 81
E.2 Connections at the terminals . 81
E.3 Construction of the terminals . 82
E.4 Fixing of the terminals . 82
Annex F (informative) Cross-reference to non-SI units . 83
Annex G (informative) Suitability of supply network for the measurement of the true
RMS value of the supply current . 84
Annex H (informative) Plotting of STATIC CHARACTERISTICS . 85
H.1 General . 85
H.2 Method . 85
H.3 Analysis of the results . 85
Annex I (normative) Test methods for a 10 Nm impact . 86
I.1 Pendulum impact hammer . 86
I.2 Free fall spherical steel weight . 86
Annex J (normative) Thickness of sheet metal for enclosures . 88
Annex K (informative) Examples of RATING PLATES . 90
Annex L (informative) Graphical symbols for arc welding equipment . 97
L.1 General . 97
L.2 Use of symbols . 97
L.3 Symbols . 98
L.4 Examples of combinations of symbols . 116
L.5 Examples of control panels . 118
Annex M (informative) Efficiency and IDLE STATE power measurement . 121
M.1 General conditions for measurement . 121
M.2 Measurements . 122
M.3 Test report . 125
M.4 Test report template . 127
Annex N (normative) TOUCH CURRENT measurement . 129
Annex O (normative) Battery-powered WELDING POWER SOURCES . 135
O.1 General . 135
O.4 Environmental conditions . 136
O.5 Tests . 136
O.6 Protection against electric shock . 138
O.7 Thermal requirements . 140
O.8 THERMAL PROTECTION . 142
O.9 Abnormal operation . 142
O.10 Connection to the supply network . 146
O.14 Mechanical provisions . 148
O.15 RATING PLATE . 149
O.17 Instructions and markings . 151
Bibliography . 153
Figure 1 – Flow chart for conformity methods of 5.3 . 26
Figure 2 – Example of insulation configuration for CLASS I EQUIPMENT . 29
Figure 3 – Measurement of WELDING CIRCUIT TOUCH CURRENT . 37
Figure 4 – Measurement of TOUCH CURRENT in normal condition . 37
Figure 5 – Measurement of RMS values . 56
Figure 6 – Measurement of peak values . 57
Figure 7 – Principle of the RATING PLATE . 66
Figure B.1 – Combined high-voltage transformers . 76
Figure C.1 – Voltage and current during AC tungsten inert-gas welding . 77
Figure C.2 – Unbalanced voltage during AC tungsten inert-gas welding . 78
Figure C.3 – AC WELDING POWER SOURCE with unbalanced load . 79
Figure I.1 – Test set-up . 86
Figure K.1 – Single-phase transformer . 90
Figure K.2 – Three-phase rotating frequency converter . 91
Figure K.3 – Subdivided RATING PLATE: single-/three-phase transformer rectifier . 92
Figure K.4 – Engine-generator-rectifier . 93
Figure K.5 – Single-/three-phase inverter type . 94
Figure K.6 – Battery-powered WELDING POWER SOURCE with INTEGRAL BATTERY . 95
Figure K.7 – Battery-powered WELDING POWER SOURCE with detachable / separable
BATTERY . 96
Figure L.1 – Input voltage power switch . 118
Figure L.2 – Arc force control potentiometer . 118
Figure L.3 – Remote receptacle and selector switches . 118
Figure L.4 – Terminals with inductance selector for MIG/MAG welding. 119
Figure L.5 – Process switch (MMA, TIG, MIG) . 119
Figure L.6 – Selector switch on AC/DC equipment . 119
Figure L.7 – Panel indicator lights (overheat, fault, arc striking, output voltage) . 119
Figure L.8 – Setting pulsing parameters using digital display . 120
Figure M.1 – Measurement procedure . 125
Figure N.1 – Measuring network, TOUCH CURRENT weighted for perception or
startle-reaction . 129
Figure N.2 – Measuring network, TOUCH CURRENT weighted for letgo-immobilization . 130
Figure N.3 – Diagram for TOUCH CURRENT measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of CLASS II . 132
Figure N.4 – Diagram for TOUCH CURRENT measurement on fault condition for three-
phase four-wire system connection of appliances other than those of CLASS II . 134
Figure O.1 – Marking of BATTERY VOLTAGE CLASS B electric components . 152
Table 1 – Alphabetical list of terms . 11
Table 2 – Minimum CLEARANCES for overvoltage category III . 30
Table 3 – Minimum CREEPAGE DISTANCES . 32
Table 4 – Insulation resistance . 33
Table 5 – Dielectric test voltages . 34
Table 6 – Minimum distance through insulation . 38
Table 7 – Temperature limits for windings, commutators and slip-rings . 43
Table 8 – Temperature limits for external surfaces . 44
Table 9 – Cross-section of the output short-circuit conductor . 47
Table 10 – Current and time requirements for PROTECTIVE CIRCUITS . 50
– 6 – IEC 60974-1:2021 © IEC 2021
Table 11 – Minimum cross-sectional area of the external protective copper conductor . 51
Table 12 – Verification of continuity of the PROTECTIVE CIRCUIT . 51
Table 13 – Pull. 52
Table 14 – Summary of allowable RATED NO-LOAD VOLTAGES . 56
Table 15 – HAZARD REDUCING DEVICE requirements . 62
Table A.1 – Nominal voltages for supply networks with protective overvoltage control . 73
Table A.2 – Single-phase three-wire or two-wire AC or DC systems . 74
Table A.3 – Three-phase four-wire or three-wire AC systems . 75
Table E.1 – Range of conductor dimensions to be accepted by the SUPPLY CIRCUIT
terminals . 81
Table F.1 – Cross-reference for mm to American wire gauge (AWG) . 83
Table I.1 – Angle of rotation θ to obtain 10 Nm impact . 86
Table I.2 – Mass of the free fall weight and height of the free fall . 87
Table J.1 – Minimum thickness of sheet metal for steel enclosures . 88
Table J.2 – Minimum thickness of sheet metal for enclosures of aluminium, brass or
copper . 89
Table L.1 – Letters used as symbols . 98
Table M.1 – Typical nominal electricity supply details for some regions . 122
Table M.2 – Load conditions for the ARC WELDING POWER SOURCE . 123
Table M.3 – Required reported data (measured and calculated). 126
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ARC WELDING EQUIPMENT –
Part 1: Welding power sources
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
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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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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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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.
IEC 60974-1 has been prepared by IEC technical committee 26: Electric welding. It is an
International Standard.
This sixth edition cancels and replaces the fifth edition published in 2017 and
Amendment 1:2019. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Table 1 with an alphabetical cross-reference listing of terms added;
b) CLEARANCE and CREEPAGE DISTANCE reference document changed to IEC 60664-1:2020;
c) 6.1.2 and 6.1.3 modified to follow IEC 60664-1 BASIC INSULATION dimensioning for mains
supply with rationalized voltages;
d) abnormal capacitor test of 6.2.2 moved to new Subclause 9.5;
e) 6.2.5 and 6.3.6 modified to use TOUCH CURRENT measuring network weighted for letgo-
immobilization and supply voltage tolerance requirement added;
f) 16.3 new structure and accuracy requirement for displayed voltage value ;
– 8 – IEC 60974-1:2021 © IEC 2021
g) Annex A changed to normative and Table A.2 and Table A.3 added;
h) Annex L editorial update to standardized symbols;
i) redraft of efficiency and IDLE STATE power measurement in Annex M based on
IEC 62301:2011;
j) Annex N measurement network weighted for letgo-immobilization added.
The text of this International Standard is based on the following documents:
FDIS Report on voting
26/724/FDIS 26/727/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
In this document, the following print types are used:
– conformity statements: in italic type.
– terms used throughout this document which have been defined in Clause 3: SMALL ROMAN
CAPITALS.
A list of all parts of the IEC 60974 series can be found, under the general title Arc welding
equipment, on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
ARC WELDING EQUIPMENT –
Part 1: Welding power sources
1 Scope
This part of IEC 60974 is applicable to power sources for arc welding and allied processes
designed for INDUSTRIAL AND PROFESSIONAL USE, and supplied by a voltage not exceeding
1 000 V, BATTERY supplied or driven by mechanical means.
This document specifies safety and performance requirements of WELDING POWER SOURCES and
PLASMA CUTTING SYSTEMS.
This document is not applicable to limited duty arc welding and cutting power sources which
are designed mainly for use by laymen and designed in accordance with IEC 60974-6.
This document includes requirements for battery-powered WELDING POWER SOURCES and
BATTERY packs, which are given in Annex O.
This document is not applicable to testing of power sources during periodic maintenance or
after repair.
NOTE 1 Typical allied processes are electric arc cutting and arc spraying.
NOTE 2 AC systems having a nominal voltage between 100 V and 1 000 V are given in Table 1 of IEC 60038:2009.
NOTE 3 This document does not include electromagnetic compatibility (EMC) requirements.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
IEC 60050-151, International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and
magnetic devices (available at: http://www.electropedia.org)
IEC 60050-851, International Electrotechnical Vocabulary (IEV) – Part 851: Electric welding
(available at: http://www.electropedia.org)
IEC 60245-6, Rubber insulated cables – Rated voltages up to and including 450/750 V – Part 6:
Arc welding electrode cables
IEC 60417, Graphical symbols for use on equipment (available at: http://www.graphical-
symbols.info/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 60664-1:2020, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
– 10 – IEC 60974-1:2021 © IEC 2021
IEC 60664-3, Insulation coordination for equipment within low-voltage systems – Part 3: Use of
coating, potting or moulding for protection against pollution
IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
IEC 60974-7, Arc welding equipment – Part 7: Torches
IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC)
requirements
IEC 61140, Protection against electric shock – Common aspects for installation and equipment
IEC 61558-2-4, Safety of transformers, reactors, power supply units and similar products for
supply voltages up to 1 100 V – Part 2-4: Particular requirements and tests for isolating
transformers and power supply units incorporating isolating transformers
IEC 61558-2-6, Safety of transformers, reactors, power supply units and similar products for
supply voltages up to 1 100 V – Part 2-6: Particular requirements and tests for safety isolating
transformers and power supply units incorporating safety isolating transformers
IEC 62133-1:2017, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for portable sealed secondary cells, and for batteries made
from them, for use in portable applications – Part 1: Nickel systems
IEC 62133-2:2017, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for portable sealed secondary lithium cells, and for batteries
made from them, for use in portable applications – Part 2: Lithium systems
IEC 62301:2011, Household electrical appliances – Measurement of standby power
ISO 7010:2019, Graphical symbols – Safety colours and safety signs – Registered safety signs
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-151,
IEC 60050-851, IEC 60664-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
Table 1 provides an alphabetical cross-reference listing of terms.
Table 1 – Alphabetical list of terms
Term Term Term Term Term Term
number number number
active power 3.3.3 explosion 3.2.23 rated reduced no-load 3.1.27
voltage
apparent power 3.3.4 fixed installation 3.1.62 rated supply current 3.1.30
basic insulation 3.1.50 flat characteristic 3.1.9 rated supply 3.3.1
frequency
basic protection 3.2.18 fully charged cell 3.2.10 rated supply voltage 3.1.29
battery 3.2.1 fully discharged cell 3.2.11 rated switched no- 3.1.28
load voltage
battery system 3.2.5 functional insulation 3.1.65 rated value 3.1.21
battery voltage class 3.2.19 general purpose 3.2.12 rating plate 3.1.22
A batteries
battery voltage class 3.2.20 hazard reducing 3.1.47 reinforced insulation 3.1.53
B device
C rate 3.2.6 idle state 3.1.66 remote control 3.1.60
cell 3.2.7 industrial and 3.1.2 routine test 3.1.6
professional use
charger 3.2.8 instructed person 3.1.4 safety extra-low 3.1.56
voltage
charging system 3.2.9 integral battery 3.2.2 separable battery 3.2.4
pack
charring 3.2.21 load voltage 3.1.14 single-fault condition 3.1.61
class I equipment 3.1.48 material group 3.1.42 specified operating 3.2.14
region
class II equipment 3.1.49 maximum charging 3.2.13 specified operating 3.2.14.1
current region for charging
class of insulation 3.1.64 maximum effective 3.1.33 static characteristic 3.1.10
supply current
clearance 3.1.38 micro-environment 3.1.41 supplementary 3.1.51
insulation
consecutive operating 3.2.22 no-load voltage 3.1.15 supply circuit 3.1.57
cycle
control circuit 3.1.12 plasma cutting power 3.1.55 temperature rise 3.1.43
source
conventional load 3.1.18 plasma cutting 3.1.54 thermal equilibrium 3.1.44
system
conventional load 3.1.20 pollution degree 3.1.40 thermal protection 3.1.45
voltage
conventional value 3.1.16 power factor 3.3.5 total harmonic 3.3.6
distortion
conventional welding 3.1.17 protective circuit 3.1.63 touch current 3.1.59
condition
conventional welding 3.1.19 rated idle speed 3.1.36 type test 3.1.5
current
creepage distance 3.1.39 rated load speed 3.1.34 upper limit charging 3.2.15
voltage
detachable battery 3.2.3 rated maximum 3.1.32 venting 3.2.16
pack supply current
double insulation 3.1.52 rated maximum 3.1.24 visual inspection 3.1.7
welding current
drooping 3.1.8 rated minimum 3.1.25 welding circuit 3.1.11
characteristic welding current
– 12 – IEC 60974-1:2021 © IEC 2021
Term Term Term Term Term Term
number number number
duty cycle 3.1.37 rated no-load speed 3.1.35 welding current 3.1.13
electronic component 3.2.17 rated no-load supply 3.1.31 welding power source 3.1.1
current
environment with 3.1.46 rated no-load voltage 3.1.26 welding power source 3.3.2
increased risk of efficiency
electric shock
expert 3.1.3 rated output 3.1.23 working voltage 3.1.58
3.1 General terms and definitions
3.1.1
welding power source
arc welding power source
equipment for supplying current and voltage and having the required characteristics suitable for
arc welding and allied processes
Note 1 to entry: A WELDING POWER SOURCE can also supply services to other equipment and auxiliaries for example
auxiliary power, cooling liquid, consumable arc welding electrode and gas to shield the arc and the welding area.
Note 2 to entry: This entry revises IEC 60050-851:2008, 851-13-01,
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