IEC 60974-1:2017

Arc welding equipment - Part 1: Welding power sources

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.
This fifth edition cancels and replaces the fourth edition published in 2012 and constitutes a technical revision.
The significant changes with respect to the previous edition are the following:
– improvement of Figure 1 (6.1.1);
– modification of Table 3 (6.1.4);
– description of energy efficiency measurements in Annex M;
– inclusion of battery supplied welding power sources in the scope. Requirements therefore are described in Annex O.

Matériel de soudage à l'arc - Partie 1: Sources de courant de soudage

La présente partie de l’IEC 60974 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.
Le présent document ne s'applique pas aux sources de courant de soudage et de coupage à l'arc à service limité qui sont utilisées essentiellement par des non professionnels et qui sont conçues selon l’IEC 60974-6.
Le présent document inclut les exigences relatives aux sources de courant de soudage alimentées par batterie et aux blocs de batteries qui sont donnés à l’Annexe O.
Le présent document ne s’applique pas aux essais des sources de courant pendant l’entretien périodique ou après réparation.
Cette cinquième édition annule et remplace la quatrième édition parue en 2012. Cette édition constitue une révision technique.
Les modifications majeures par rapport à l’édition précédente sont les suivantes:
– amélioration de la Figure 1 (6.1.1);
– modification du Tableau 3 (6.1.4);
– description des mesurages du rendement énergétique dans l’Annexe M;
– introduction des sources de courant de soudage alimentées par batterie dans le domaine d’application. Les exigences sont donc décrites dans l’Annexe O.

General Information

• Status: Published
• Publication Date: 07-Feb-2017
• ICS: 25.160.30 - Welding equipment
• Technical Committee: TC 26 - Electric welding
• Drafting Committee: WG 1 - TC 26/WG 1
• Current Stage: DELPUB - Deleted Publication
• Start Date: 29-Jun-2021
• Completion Date: 12-Aug-2021

Relations

• Amended By: IEC 60974-1:2017/AMD1:2019 - Amendment 1 - Arc welding equipment - Part 1: Welding power sources
• Effective Date: 05-Sep-2023
• Revised: IEC 60974-1:2021 - Arc welding equipment - Part 1: Welding power sources
• Effective Date: 05-Sep-2023
• Revises: IEC 60974-1:2012 - Arc welding equipment - Part 1: Welding power sources
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60974-1 ®
Edition 5.1 2019-01
CONSOLIDATED VERSION
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

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from

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IEC 60974-1 ®
Edition 5.1 2019-01
CONSOLIDATED VERSION
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 978-2-8322-6429-4

IEC 60974-1 ®
Edition 5.1 2019-01
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Arc welding equipment –
Part 1: Welding power sources
Matériel de soudage à l’arc –
Partie 1: Sources de courant de soudage

– 2 – IEC 60974-1:2017+AMD1:2019 CSV

© IEC 2019
CONTENTS
FOREWORD . 9

1 Scope . 11

2 Normative references . 11

3 Terms and definitions . 12

3.1 General terms . 12

3.2 Terms related to battery systems . 21

4 Environmental conditions . 24

5 Tests . 25
5.1 Test conditions . 25
5.2 Measuring instruments . 25
5.3 Conformity of components . 25
5.4 Type tests . 26
5.5 Routine tests. 26
6 Protection against electric shock . 27
6.1 Insulation . 27
6.1.1 General . 27
6.1.2 Clearances . 28
6.1.3 Creepage distances . 30
6.1.4 Insulation resistance . 32
6.1.5 Dielectric strength . 32
6.2 Protection against electric shock in normal service (direct contact) . 34
6.2.1 Protection provided by the enclosure . 34
6.2.2 Capacitors . 34
6.2.3 Automatic discharge of supply circuit capacitors . 35
6.2.4 Isolation of the welding circuit . 35
6.2.5 Welding circuit touch current . 35
6.2.6 Touch current in normal condition . 36
6.3 Protection against electric shock in case of a fault condition (indirect contact)
............................................................................................................................. 37
6.3.1 Protective provisions . 37
6.3.2 Isolation between windings of the supply circuit and the welding circuit . 37
6.3.3 Internal conductors and connections . 37

6.3.4 Additional requirements for plasma cutting systems . 38
6.3.5 Movable coils and cores . 38
6.3.6 Touch current in fault condition . 38
7 Thermal requirements . 39
7.1 Heating test . 39
7.1.1 Test conditions . 39
7.1.2 Tolerances of the test parameters . 39
7.1.3 Duration of test . 40
7.2 Temperature measurement . 40
7.2.1 Measurement conditions . 40
7.2.2 Surface temperature sensor . 40
7.2.3 Resistance . 40
7.2.4 Embedded temperature sensor . 41

© IEC 2019
7.2.5 Determination of the ambient air temperature . 41

7.2.6 Recording of temperatures . 41

7.3 Limits of temperature rise . 41

7.3.1 Windings, commutators and slip-rings . 41

7.3.2 External surfaces . 42

7.3.3 Other components . 43

7.4 Loading test . 43

7.5 Commutators and slip-rings . 44

8 Thermal protection. 44

8.1 General requirements . 44
8.2 Construction . 44
8.3 Location . 44
8.4 Operating capacity . 44
8.5 Operation . 45
8.6 Resetting . 45
8.7 Indication . 45
9 Abnormal operation . 45
9.1 General requirements . 45
9.2 Stalled fan test . 46
9.3 Short circuit test . 46
9.4 Overload test . 47
10 Connection to the supply network . 47
10.1 Supply voltage . 47
10.2 Multi-supply voltage . 47
10.3 Means of connection to the supply circuit . 47
10.4 Marking of terminals . 48
10.5 Protective circuit . 48
10.5.1 Continuity requirement . 48
10.5.2 Type test . 49
10.5.3 Routine test . 49
10.6 Cable anchorage . 50
10.7 Inlet openings . 51
10.8 Supply circuit on/off switching device . 51
10.9 Supply cables . 52
10.10 Supply coupling device (attachment plug) . 52

11 Output . 53
11.1 Rated no-load voltage . 53
11.1.1 Rated no-load voltage for use in environments with increased risk of
electric shock . 53
11.1.2 Rated no-load voltage for use in environments without increased risk of
electric shock . 53
11.1.3 Rated no-load voltage for the use with mechanically held torches with
increased protection for the operator . 53
11.1.4 Rated no-load voltage for special processes for example plasma cutting . 53
11.1.5 Additional requirements . 54
11.1.6 Measuring circuits . 55
11.2 Type test values of the conventional load voltage . 56
11.2.1 Manual metal arc welding with covered electrodes . 56
11.2.2 Tungsten inert gas . 56

– 4 – IEC 60974-1:2017+AMD1:2019 CSV

© IEC 2019
11.2.3 Metal inert/active gas and flux cored arc welding . 56

11.2.4 Submerged arc welding . 56

11.2.5 Plasma cutting . 56

11.2.6 Plasma welding . 56

11.2.7 Plasma gouging . 56

11.2.8 Additional requirements . 56

11.3 Mechanical switching devices used to adjust output . 57

11.4 Welding circuit connections . 57

11.4.1 Protection against unintentional contact . 57

11.4.2 Location of coupling devices . 57

11.4.3 Outlet openings . 57
11.4.4 Three-phase multi-operator welding transformer . 57
11.4.5 Marking . 58
11.4.6 Connections for plasma cutting torches . 58
11.5 Power supply to external devices connected to the welding circuit . 58
11.6 Auxiliary power supply . 58
11.7 Welding cables . 59
12 Control circuits . 59
12.1 General requirement . 59
12.2 Isolation of control circuits . 59
12.3 Working voltages of remote control circuits . 59
13 Hazard reducing device . 60
13.1 General requirements . 60
13.2 Types of hazard reducing devices . 60
13.2.1 Voltage reducing device . 60
13.2.2 Switching device for AC to DC . 60
13.3 Requirements for hazard reducing devices . 60
13.3.1 Disabling the hazard reducing device . 60
13.3.2 Interference with operation of a hazard reducing device . 61
13.3.3 Indication of satisfactory operation . 61
13.3.4 Fail to a safe condition . 61
14 Mechanical provisions . 61
14.1 General requirements . 61
14.2 Enclosure . 61
14.2.1 Enclosure materials . 61

14.2.2 Enclosure strength . 62
14.3 Handling means . 62
14.3.1 Mechanised handling . 62
14.3.2 Manual handling . 62
14.4 Drop withstand . 63
14.5 Tilting stability . 63
15 Rating plate . 63
15.1 General requirements . 63
15.2 Description . 64
15.3 Contents . 65
15.4 Tolerances . 68
15.5 Direction of rotation . 68
16 Adjustment of the output . 68

© IEC 2019
16.1 Type of adjustment . 68

16.2 Marking of the adjusting device . 69

16.3 Indication of current or voltage control . 69

17 Instructions and markings . 70

17.1 Instructions . 70

17.2 Markings . 71

Annex A (informative) Nominal voltages of supply networks . 72

Annex B (informative) Example of a combined dielectric test . 73

Annex C (normative) Unbalanced load in case of AC tungsten inert-gas welding power

sources . 74
C.1 General . 74
C.2 Unbalanced load . 74
C.3 Example for an unbalanced load . 75
Annex D (informative) Extrapolation of temperature to time of shutdown . 76
Annex E (normative) Construction of supply circuit terminals . 77
E.1 Size of terminals . 77
E.2 Connections at the terminals . 77
E.3 Construction of the terminals . 78
E.4 Fixing of the terminals . 78
Annex F (informative) Cross-reference to non-SI units . 79
Annex G (informative) Suitability of supply network for the measurement of the true
r.m.s. value of the supply current . 80
Annex H (informative) Plotting of static characteristics . 81
H.1 General . 81
H.2 Method . 81
H.3 Analysis of the results . 81
Annex I (normative) Test methods for a 10 Nm impact . 82
I.1 Pendulum impact hammer . 82
I.2 Free fall spherical steel weight . 83
Annex J (normative) Thickness of sheet metal for enclosures . 84
Annex K (informative) Examples of rating plates . 87
Annex L (informative) Graphical symbols for arc welding equipment . 94
L.1 General . 94
L.2 Use of symbols . 94

L.2.1 General . 94
L.2.2 Selection of symbols . 94
L.2.3 Size of symbols . 94
L.2.4 Use of colour . 94
L.3 Symbols . 95
L.3.1 General . 95
L.3.2 Letter symbols . 95
L.3.3 Graphical symbols . 96
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 Measuring efficiency . 121
M.2 Measuring idle state power . 121

– 6 – IEC 60974-1:2017+AMD1:2019 CSV

© IEC 2019
Annex N (normative) Touch current measurement in fault condition . 123

Annex O (normative) Battery-powered welding power sources . 128

O.1 General . 128

O.4 Environmental conditions . 129

O.5 Tests . 129

O.5.1 Test conditions . 129

O.5.3 Conformity of components . 130

O.6 Protection against electric shock . 131

O.6.1 Insulation . 131

O.6.2 Protection against electric shock in normal service . 132
O.7 Thermal requirements . 133
O.7.1 Heating test . 133
O.7.2 Temperature measurement . 134
O.7.4 Loading test . 134
O.7.201 Normal charging of lithium-ion systems . 134
O.8 Thermal protection . 135
O.8.1 General requirements . 135
O.8.4 Operating capacity . 135
O.9 Abnormal operation . 135
O.9.1 General requirements . 135
O.9.2 Stalled fan test . 136
O.9.3 Short circuit test . 136
O.9.4 Overload test . 136
O.9.201 Welding power source – abnormal conditions . 136
O.9.202 Welding circuit components – abnormal conditions . 137
O.9.203 Lithium-ion charging systems − abnormal conditions . 137
O.9.204 Lithium-ion battery short circuit . 138
O.9.205 Batteries other than lithium-ion – overcharging . 139
O.9.206 Battery pack disconnection . 139
O.9.207 General purpose batteries . 139
O.10 Connection to the supply network . 139
O.10.5 Protective circuit . 140
O.10.8 Supply circuit on/off switching device . 140
O.14 Mechanical provisions . 141
O.14.1 General requirements . 141

O.14.2 Enclosure . 141
O.14.4 Drop withstand . 141
O.15 Rating plate . 142
O.15.3 Contents . 142
O.17 Instructions and markings . 144
O.17.1 Instructions . 144
O.17.2 Markings . 145
Annex P (normative) Conformity of components . 146
Bibliography . 148

Figure 1 – Example of insulation configuration for Class I equipment . 28
Figure 2 – Measurement of welding circuit touch current . 36
Figure 3 – Measurement of touch current in normal condition . 36

© IEC 2019
Figure 4 – Measurement of r.m.s. values . 55

Figure 5 – Measurement of peak values . 55

Figure 6 – Principle of the rating plate . 64

Figure B.1 – Combined high-voltage transformers . 73

Figure C.1 – Voltage and current during AC tungsten inert-gas welding . 74

Figure C.2 – Unbalanced voltage during AC tungsten inert-gas welding . 75

Figure C.3 – AC welding power source with unbalanced load . 75

Figure I.1 – Test set-up . 82

Figure K.1 – Single-phase transformer . 87
Figure K.2 – Three-phase rotating frequency converter . 88
Figure K.3 – Subdivided rating plate: single-/three-phase transformer rectifier . 89
Figure K.4 – Engine-generator-rectifier . 90
Figure K.5 – Single-/three-phase inverter type . 91
Figure K.6 – Battery powered welding power source with integral battery . 92
Figure K.7 – Battery powered welding power source with detachable / separable
battery . 93
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. 119
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 . 120
Figure N.1 – Measuring network for weighted touch current . 123
Figure N.2 – Diagram for touch current measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of class II . 125
Figure N.3 – Diagram for touch current measurement on fault condition for three-phase
four-wire system connection of appliances other than those of class II . 127
Figure O.1 – Marking of battery voltage class B electric components . 145
Figure P.1 – Flow chart for conformity methods of Annex P . 147

Table 1 – Minimum clearances for overvoltage category III . 29
Table 2 – Minimum creepage distances . 31
Table 3 – Insulation resistance . 32
Table 4 – Dielectric test voltages . 33
Table 5 – Minimum distance through insulation . 37
Table 6 – Temperature limits for windings, commutators and slip-rings . 42
Table 7 – Temperature limits for external surfaces . 43
Table 8 – Cross-section of the output short-circuit conductor . 46
Table 9 – Current and time requirements for protective circuits . 49
Table 10 – Minimum cross-sectional area of the external protective copper conductor . 49
Table 11 – Verification of continuity of the protective circuit . 50
Table 12 – Pull. 51

– 8 – IEC 60974-1:2017+AMD1:2019 CSV

© IEC 2019
Table 13 – Summary of allowable rated no-load voltages . 54

Table 14 – Hazard reducing device requirements . 60

Table E.1 – Range of conductor dimensions to be accepted by the supply circuit

terminals . 77

Table F.1 – Cross-reference for mm to American wire gauge (AWG) . 79

Table I.1 – Angle of rotation θ to obtain 10 Nm impact . 83

Table I.2 – Mass of the free fall weight and height of the free fall . 84

Table J.1 – Minimum thickness of sheet metal for steel enclosures . 86

Table J.2 – Minimum thickness of sheet metal for enclosures of aluminium, brass or

copper . 87
Table L.1 – Letters used as symbols . 96

© IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
ARC WELDING EQUIPMENT –
Part 1: Welding power sources
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IEC 60974-1 ®
Edition 5.0 2017-02
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

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
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IEC 60974-1 ®
Edition 5.0 2017-02
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 978-2-8322-3854-7

– 2 – IEC 60974-1:2017 © IEC 2017
CONTENTS
FOREWORD . 9
1 Scope . 11
2 Normative references . 11
3 Terms and definitions . 12
3.1 General terms . 12
3.2 Terms related to battery systems . 21
4 Environmental conditions . 24
5 Tests . 25
5.1 Test conditions . 25
5.2 Measuring instruments . 25
5.3 Conformity of components . 25
5.4 Type tests . 26
5.5 Routine tests. 26
6 Protection against electric shock . 27
6.1 Insulation . 27
6.1.1 General . 27
6.1.2 Clearances . 28
6.1.3 Creepage distances . 30
6.1.4 Insulation resistance . 32
6.1.5 Dielectric strength . 32
6.2 Protection against electric shock in normal service (direct contact) . 34
6.2.1 Protection provided by the enclosure . 34
6.2.2 Capacitors . 34
6.2.3 Automatic discharge of supply circuit capacitors . 35
6.2.4 Isolation of the welding circuit . 35
6.2.5 Welding circuit touch current . 35
6.2.6 Touch current in normal condition . 36
6.3 Protection against electric shock in case of a fault condition (indirect contact)
............................................................................................................................. 37
6.3.1 Protective provisions . 37
6.3.2 Isolation between windings of the supply circuit and the welding circuit . 37
6.3.3 Internal conductors and connections . 37
6.3.4 Additional requirements for plasma cutting systems . 38
6.3.5 Movable coils and cores . 38
6.3.6 Touch current in fault condition . 38
7 Thermal requirements . 39
7.1 Heating test . 39
7.1.1 Test conditions . 39
7.1.2 Tolerances of the test parameters . 39
7.1.3 Duration of test . 40
7.2 Temperature measurement . 40
7.2.1 Measurement 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 air temperature . 41

7.2.6 Recording of temperatures . 41
7.3 Limits of temperature rise . 41
7.3.1 Windings, commutators and slip-rings . 41
7.3.2 External surfaces . 42
7.3.3 Other components . 43
7.4 Loading test . 43
7.5 Commutators and slip-rings . 44
8 Thermal protection. 44
8.1 General requirements . 44
8.2 Construction . 44
8.3 Location . 44
8.4 Operating capacity . 44
8.5 Operation . 45
8.6 Resetting . 45
8.7 Indication . 45
9 Abnormal operation . 45
9.1 General requirements . 45
9.2 Stalled fan test . 46
9.3 Short circuit test . 46
9.4 Overload test . 47
10 Connection to the supply network . 47
10.1 Supply voltage . 47
10.2 Multi-supply voltage . 47
10.3 Means of connection to the supply circuit . 47
10.4 Marking of terminals . 48
10.5 Protective circuit . 48
10.5.1 Continuity requirement . 48
10.5.2 Type test . 49
10.5.3 Routine test . 49
10.6 Cable anchorage . 50
10.7 Inlet openings . 51
10.8 Supply circuit on/off switching device . 51
10.9 Supply cables . 52
10.10 Supply coupling device (attachment plug) . 52
11 Output . 53
11.1 Rated no-load voltage . 53
11.1.1 Rated no-load voltage for use in environments with increased risk of
electric shock . 53
11.1.2 Rated no-load voltage for use in environments without increased risk of
electric shock . 53
11.1.3 Rated no-load voltage for the use with mechanically held torches with
increased protection for the operator . 53
11.1.4 Rated no-load voltage for special processes for example plasma cutting . 53
11.1.5 Additional requirements . 54
11.1.6 Measuring circuits . 55
11.2 Type test values of the conventional load voltage . 56
11.2.1 Manual metal arc welding with covered electrodes . 56
11.2.2 Tungsten inert gas . 56
11.2.3 Metal inert/active gas and flux cored arc welding . 56

– 4 – IEC 60974-1:2017 © IEC 2017
11.2.4 Submerged arc welding . 56
11.2.5 Plasma cutting . 56
11.2.6 Plasma welding . 56
11.2.7 Plasma gouging . 56
11.2.8 Additional requirements . 56
11.3 Mechanical switching devices used to adjust output . 57
11.4 Welding circuit connections . 57
11.4.1 Protection against unintentional contact . 57
11.4.2 Location of coupling devices . 57
11.4.3 Outlet openings . 57
11.4.4 Three-phase multi-operator welding transformer . 57
11.4.5 Marking . 58
11.4.6 Connections for plasma cutting torches . 58
11.5 Power supply to external devices connected to the welding circuit . 58
11.6 Auxiliary power supply . 58
11.7 Welding cables . 59
12 Control circuits . 59
12.1 General requirement . 59
12.2 Isolation of control circuits . 59
12.3 Working voltages of remote control circuits . 59
13 Hazard reducing device . 60
13.1 General requirements . 60
13.2 Types of hazard reducing devices . 60
13.2.1 Voltage reducing device . 60
13.2.2 Switching device for AC to DC . 60
13.3 Requirements for hazard reducing devices . 60
13.3.1 Disabling the hazard reducing device . 60
13.3.2 Interference with operation of a hazard reducing device . 61
13.3.3 Indication of satisfactory operation . 61
13.3.4 Fail to a safe condition . 61
14 Mechanical provisions . 61
14.1 General requirements . 61
14.2 Enclosure . 61
14.2.1 Enclosure materials . 61
14.2.2 Enclosure strength . 62
14.3 Handling means . 62
14.3.1 Mechanised handling . 62
14.3.2 Manual handling . 62
14.4 Drop withstand . 63
14.5 Tilting stability . 63
15 Rating plate . 63
15.1 General requirements . 63
15.2 Description . 64
15.3 Contents . 65
15.4 Tolerances . 68
15.5 Direction of rotation . 68
16 Adjustment of the output . 68
16.1 Type of adjustment . 68

16.2 Marking of the adjusting device . 69
16.3 Indication of current or voltage control . 69
17 Instructions and markings . 70
17.1 Instructions . 70
17.2 Markings . 71
Annex A (informative) Nominal voltages of supply networks . 72
Annex B (informative) Example of a combined dielectric test . 73
Annex C (normative) Unbalanced load in case of AC tungsten inert-gas welding power
sources . 74
C.1 General . 74
C.2 Unbalanced load . 74
C.3 Example for an unbalanced load . 75
Annex D (informative) Extrapolation of temperature to time of shutdown . 76
Annex E (normative) Construction of supply circuit terminals . 77
E.1 Size of terminals . 77
E.2 Connections at the terminals . 77
E.3 Construction of the terminals . 78
E.4 Fixing of the terminals . 78
Annex F (informative) Cross-reference to non-SI units . 79
Annex G (informative) Suitability of supply network for the measurement of the true
r.m.s. value of the supply current . 80
Annex H (informative) Plotting of static characteristics . 81
H.1 General . 81
H.2 Method . 81
H.3 Analysis of the results . 81
Annex I (normative) Test methods for a 10 Nm impact . 82
I.1 Pendulum impact hammer . 82
I.2 Free fall spherical steel weight . 83
Annex J (normative) Thickness of sheet metal for enclosures . 84
Annex K (informative) Examples of rating plates . 87
Annex L (informative) Graphical symbols for arc welding equipment . 94
L.1 General . 94
L.2 Use of symbols . 94
L.2.1 General . 94
L.2.2 Selection of symbols . 94
L.2.3 Size of symbols . 94
L.2.4 Use of colour . 94
L.3 Symbols . 95
L.3.1 General . 95
L.3.2 Letter symbols . 95
L.3.3 Graphical symbols . 96
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 Measuring efficiency . 121
M.2 Measuring idle state power . 121
Annex N (normative) Touch current measurement in fault condition . 123

– 6 – IEC 60974-1:2017 © IEC 2017
Annex O (normative) Battery-powered welding power sources . 128
O.1 General . 128
O.4 Environmental conditions . 129
O.5 Tests . 129
O.5.1 Test conditions . 129
O.5.3 Conformity of components . 130
O.6 Protection against electric shock . 131
O.6.1 Insulation . 131
O.6.2 Protection against electric shock in normal service . 132
O.7 Thermal requirements . 133
O.7.1 Heating test . 133
O.7.2 Temperature measurement . 134
O.7.4 Loading test . 134
O.7.201 Normal charging of lithium-ion systems . 134
O.8 Thermal protection . 135
O.8.1 General requirements . 135
O.8.4 Operating capacity . 135
O.9 Abnormal operation . 135
O.9.1 General requirements . 135
O.9.2 Stalled fan test . 136
O.9.3 Short circuit test . 136
O.9.4 Overload test . 136
O.9.201 Welding power source – abnormal conditions . 136
O.9.202 Welding circuit components – abnormal conditions . 137
O.9.203 Lithium-ion charging systems − abnormal conditions . 137
O.9.204 Lithium-ion battery short circuit . 138
O.9.205 Batteries other than lithium-ion – overcharging . 139
O.9.206 Battery pack disconnection . 139
O.9.207 General purpose batteries . 139
O.10 Connection to the supply network . 139
O.10.5 Protective circuit . 140
O.10.8 Supply circuit on/off switching device . 140
O.14 Mechanical provisions . 141
O.14.1 General requirements . 141
O.14.2 Enclosure . 141
O.14.4 Drop withstand . 141
O.15 Rating plate . 142
O.15.3 Contents . 142
O.17 Instructions and markings . 144
O.17.1 Instructions . 144
O.17.2 Markings . 145
Bibliography . 146

Figure 1 – Example of insulation configuration for Class I equipment . 28
Figure 2 – Measurement of welding circuit touch current . 36
Figure 3 – Measurement of touch current in normal condition . 36
Figure 4 – Measurement of r.m.s. values . 55
Figure 5 – Measurement of peak values . 55

Figure 6 – Principle of the rating plate . 64
Figure B.1 – Combined high-voltage transformers . 73
Figure C.1 – Voltage and current during AC tungsten inert-gas welding . 74
Figure C.2 – Unbalanced voltage during AC tungsten inert-gas welding . 75
Figure C.3 – AC welding power source with unbalanced load . 75
Figure I.1 – Test set-up . 82
Figure K.1 – Single-phase transformer . 87
Figure K.2 – Three-phase rotating frequency converter . 88
Figure K.3 – Subdivided rating plate: single-/three-phase transformer rectifier . 89
Figure K.4 – Engine-generator-rectifier . 90
Figure K.5 – Single-/three-phase inverter type . 91
Figure K.6 – Battery powered welding power source with integral battery . 92
Figure K.7 – Battery powered welding power source with detachable / separable
battery . 93
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. 119
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 . 120
Figure N.1 – Measuring network for weighted touch current . 123
Figure N.2 – Diagram for touch current measurement on fault condition at operating
temperature for single-phase connection of appliances other than those of class II . 125
Figure N.3 – Diagram for touch current measurement on fault condition for three-phase
four-wire system connection of appliances other than those of class II . 127
Figure O.1 – Marking of battery voltage class B electric components . 145

Table 1 – Minimum clearances for overvoltage category III . 29
Table 2 – Minimum creepage distances . 31
Table 3 – Insulation resistance . 32
Table 4 – Dielectric test voltages . 33
Table 5 – Minimum distance through insulation . 37
Table 6 – Temperature limits for windings, commutators and slip-rings . 42
Table 7 – Temperature limits for external surfaces . 43
Table 8 – Cross-section of the output short-circuit conductor . 46
Table 9 – Current and time requirements for protective circuits . 49
Table 10 – Minimum cross-sectional area of the external protective copper conductor . 49
Table 11 – Verification of continuity of the protective circuit . 50
Table 12 – Pull. 51
Table 13 – Summary of allowable rated no-load voltages . 54
Table 14 – Hazard reducing device requirements . 60

– 8 – IEC 60974-1:2017 © IEC 2017
Table E.1 – Range of conductor dimensions to be accepted by the supply circuit
terminals . 77
Table F.1 – Cross-reference for mm to American wire gauge (AWG) . 79
Table I.1 – Angle of rotation θ to obtain 10 Nm impact . 82
Table I.2 – Mass of the free fall weight and height of the free fall . 83
Table J.1 – Minimum thickness of sheet metal for steel enclosures . 85
Table J.2 – Minimum thickness of sheet metal for enclosures of aluminium, brass or
copper . 86
Table L.1 – Letters used as symbols . 95

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ARC WELDING EQUIPMENT –
Part 1: Welding power sources
FOREWORD
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International Standard IEC 60974-1 has been prepared by IEC technical committee 26:
Electric welding.
This fifth edition cancels and replaces the fourth edition published in 2012 and constitutes a
technical revision.
The significant changes with respect to the previous edition are the following:
– improvement of Figure 1 (6.1.1);
– modification of Table 3 (6.1.4);
...