IEC 60974-9:2010
(Main)Arc welding equipment - Part 9: Installation and use
Arc welding equipment - Part 9: Installation and use
IEC 60974-9:2010 is applicable to the installation and use of equipment for arc welding and allied processes designed in accordance with safety requirements of IEC 60974-1, IEC 60974-6 or equivalent. This part of IEC 60974 is applicable for the guidance of instructors, operators, welders, managers, and supervisors in the safe installation and use of equipment for arc welding and allied processes and the safe performance of welding and cutting operations. It cancels and replaces IEC/TS 62081, published in 1999. This first edition constitutes a technical revision. The following major differences with respect to IEC/TS 62081:1999 are to be noted:
- 4.3.3 Welding cables: Now dimensions are recommended;
- 5 Electromagnetic compatibility (EMC): this is completely new;
- 6 Electromagnetic fields (EMF): this is completely new;
- 7.3 Inspection and maintenance of the welding installation: There is now a differentiation between periodical and routine inspection.
Matériel de soudage à l'arc - Partie 9: Installation et utilisation
La CEI 60974-9:2010 est applicable à l'installation et à l'utilisation du matériel pour le soudage à l'arc et les procédés connexes conçus selon les exigences de sécurité de la CEI 60974-1, de la CEI 60974-6 ou équivalent. La présente partie de la CEI 60974 est applicable pour guider les instructeurs, les opérateurs, les soudeurs, les gestionnaires, et les superviseurs pour obtenir une installation et une utilisation sûres du matériel pour le soudage à l'arc et les techniques connexes et obtenir des performances sûres dans les opérations de soudage et de coupage. Cette première édition constitue une révision technique. Les modifications majeures par rapport à la CEI/TS 62081:1999 sont les suivantes:
- 4.3.3 Câbles de soudage: les dimensions sont maintenant recommandées;
- 5 Compatibilité électromagnétique (CEM): nouvel article;
- 6 Champs électromagnétiques (CEM): nouvel article;
- 7.3 Examen et maintenance de l'installation de soudage: on maintenant fait la différence entre examen périodique et examen quotidien.
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Standards Content (Sample)
IEC 60974-9 ®
Edition 1.0 2010-01
INTERNATIONAL
STANDARD
Arc welding equipment –
Part 9: Installation and use
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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IEC 60974-9 ®
Edition 1.0 2010-01
INTERNATIONAL
STANDARD
Arc welding equipment –
Part 9: Installation and use
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
U
ICS 25.160.30 ISBN 978-2-88910-363-8
– 2 – 60974-9 © IEC:2010(E)
CONTENTS
FOREWORD.4
1 Scope.6
2 Normative references.6
3 Terms and definitions .6
4 Installation.8
4.1 General .8
4.2 Supply circuit.8
4.2.1 Selection of supply cables.8
4.2.2 Supply disconnecting device .8
4.2.3 Emergency stopping device.8
4.3 Welding circuit.9
4.3.1 Isolation from the input supply.9
4.3.2 Summation of no-load voltages .9
4.3.3 Welding cables .9
4.3.4 Connection between the welding power source and the workpiece.9
4.3.5 Earthing of the workpiece.10
4.3.6 Location of gas cylinders.11
5 Electromagnetic compatibility (EMC) .11
5.1 General .11
5.2 Assessment of area.11
5.3 Methods of reducing emissions .11
5.3.1 Public supply system.11
5.3.2 Maintenance of arc welding equipment.12
5.3.3 Welding cables .12
5.3.4 Equipotential bonding.12
5.3.5 Earthing of the workpiece.12
5.3.6 Screening and shielding.12
6 Electromagnetic fields (EMF) .12
7 Use .13
7.1 General requirements .13
7.2 Connection between several welding power sources .13
7.3 Inspection and maintenance of the welding installation.13
7.3.1 Periodical inspection.13
7.3.2 Routine inspection .13
7.4 Disconnection of welding power sources and/or welding circuits .14
7.5 Guards .14
7.6 Information for operators .14
7.7 Protective measures .14
7.7.1 Extraneous conductive parts in the welding area .14
7.7.2 Protection against electric shock .14
7.8 Isolation of the welding circuit from the workpiece and earth when not in use .14
7.9 Voltage between electrode holders or torches .15
7.10 Welding in an environment with increased hazard of electric shock .17
7.11 Use of shoulder slings .17
7.12 Welding at elevated positions .18
60974-9 © IEC:2010(E) – 3 –
7.13 Welding with suspended welding equipment.18
Annex A (informative) Hazards associated with arc welding .19
Annex B (informative) Voltage drops in the welding circuit .25
Bibliography .27
Figure 1 – Example of d.c. voltage between electrode holders or torches.15
Figure 2 – Example of a.c. voltage between electrode holders or torches – Single-phase
supply from the same pair of lines of a three-phase mains supply .16
Figure 3 – Example of a.c. voltage between electrode holders or torches – Single-phase
supply from different pairs of lines of a three-phase mains supply.16
Figure 4 – Example of a.c. voltage between electrode holders connected between
different lines of output.17
Figure A.1 – Steps for the control of welding fume .22
Figure A.2 – Steps of operation for work in confined spaces .24
Figure B.1 – Example of MIG/MAG equipment.25
Table 1 – Current ratings for copper welding cables.9
Table B.1 – Voltage drop in copper and aluminium welding cables at normal and
elevated temperatures.26
– 4 – 60974-9 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ARC WELDING EQUIPMENT –
Part 9: Installation and use
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
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
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60974-9 has been prepared by IEC technical committee 26: Electric
welding.
This standard cancels and replaces IEC/TS 62081, published in 1999. This first edition
constitutes a technical revision. The following major differences with respect to
IEC/TS 62081:1999 are to be noted:
• 4.3.3 Welding cables: Now dimensions are recommended.
• 5 Electromagnetic compatibility (EMC): this is completely new.
• 6 Electromagnetic fields (EMF) : this is completely new.
60974-9 © IEC:2010(E) – 5 –
• 7.3 Inspection and maintenance of the welding installation: There is now a
differentiation between periodical and routine inspection.
The text of this part of IEC 60974 is based on the following documents:
FDIS Report on voting
26/404/FDIS 26/405/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The list of all the parts of the IEC 60974 series, under the general title Arc welding equipment,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this standard may be issued at a later date.
– 6 – 60974-9 © IEC:2010(E)
ARC WELDING EQUIPMENT –
Part 9: Installation and use
1 Scope
This part of IEC 60974 is applicable to the installation and use of equipment for arc welding
and allied processes designed in accordance with safety requirements of IEC 60974-1,
IEC 60974-6 or equivalent.
This part of IEC 60974 is applicable for the guidance of instructors, operators, welders,
managers, and supervisors in the safe installation and use of equipment for arc welding and
allied processes and the safe performance of welding and cutting operations.
National and local regulations take precedence over this part of IEC 60974.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60245-6, Rubber insulated cables – Rated voltages up to and including 450/750 V – Part 6:
Arc welding electrode cables
IEC/TR 60755, General requirements for residual current operated protective devices
IEC 60974-1:2005, Arc welding equipment – Part 1: Welding power sources
IEC 60974-4, Arc welding equipment – Part 4: In-service inspection and testing
IEC 60974-6, Arc welding equipment – Part 6: Limited duty manual metal arc welding power
sources
IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC)
requirements
IEC 60974-11, Arc welding equipment – Part 11: Electrode holders
IEC 60974-12, Arc welding equipment – Part 12: Coupling devices for welding cables
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
welding circuit
circuit that includes all conductive material through which the welding current is intended to
flow
60974-9 © IEC:2010(E) – 7 –
NOTE 1 In arc welding, the arc is a part of the welding circuit.
NOTE 2 In certain arc welding processes, the arc may be established between two electrodes. In such a case, the
workpiece is not necessarily a part of the welding circuit.
[IEC 60974-1:2005, 3.11]
3.2
extraneous conductive part
conductive part not forming part of the electrical installation and liable to introduce an electric
potential, generally the earth potential
NOTE Electrical installation includes the welding circuit.
3.3
workpiece
metal piece or pieces on which welding or allied processes are performed
3.4
protective clothing and accessories
protective clothing and accessories (e.g. gloves, hand shields, head masks and filter lenses)
used in order to diminish electric shock risks and the effects of fume and spatter and to protect
the skin and eyes against arc radiation
3.5
environments with increased hazard of electric shock
environments where the hazard of electric shock by arc welding is increased in relation to
normal arc welding conditions
NOTE 1 Such environments are found for example
a) in locations in which freedom of movement is restricted, so that the operator is forced to perform the welding in
a cramped (for example kneeling, sitting, lying) position with physical contact with conductive parts;
b) in locations which are fully or partially limited by conductive elements and in which there is a high risk of
unavoidable or accidental contact by the operator;
c) in wet, damp or hot locations where humidity or perspiration considerably reduces the skin resistance of the
human body and the insulating properties of accessories.
NOTE 2 Environments with increased hazard of electric shock are not meant to include places where electrically
conductive parts in the near vicinity of the operator which can cause increased hazard have been insulated.
[IEC 60974-1:2005, 3.46]
3.6
industrial and professional use
use intended only for experts or instructed persons
[IEC 60974-1:2005, 3.2]
3.7
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 Several years of practice in the relevant technical field may be taken into consideration in assessment of
professional training.
[IEC 60974-1:2005, 3.3]
– 8 – 60974-9 © IEC:2010(E)
3.8
wire feeder
equipment that delivers filler wire to the arc or weld zone which includes the wire-feed control
and means to apply motion to the filler wire and may also include the filler wire supply
[IEC 60974-5:2007, 3.11]
3.9
auxiliary power output
circuit of a welding power source designed to provide electrical power to auxiliary equipment
4 Installation
4.1 General
Welding equipment used in arc welding installations shall be intended for the purpose and shall
be built in accordance with IEC 60974-1, IEC 60974-4, IEC 60974-6, IEC 60974-10, IEC 60974-
11 and IEC 60974-12 (see Clause 2), as given on the rating plate.
Electromagnetic compatibility (EMC) requirements shall be taken into consideration during
installation, see Clause 5.
The requirements of national and local regulations shall be taken into consideration during
installation, including grounding or protective earth connections, fuses, supply disconnecting
device, type of supply circuit, etc.
Read the manufacturers’ instruction manual before installing the equipment. Full use shall be
made of the technical information relevant to the welding equipment.
Specific advice may be obtained from the welding equipment manufacturer if necessary.
4.2 Supply circuit
4.2.1 Selection of supply cables
Supply cables for welding equipment and their overload protection, if not provided by the
manufacturer, shall be selected in accordance with the information given in the manufacturers’
instruction manual.
Supply cables shall be placed, so that they cannot be damaged in use. If that cannot be
achieved, a sensitive residual current circuit breaker, capable of operating at a leakage current
not exceeding 30 mA in accordance with IEC/TR 60755 shall be used to reduce the risk of
electric shock.
4.2.2 Supply disconnecting device
The installer shall ensure that a supply disconnecting device is fitted at the point of supply.
NOTE A plug may be used as supply disconnecting device in accordance with national or local regulation.
4.2.3 Emergency stopping device
When an emergency stopping device is required by national regulation (e.g. automatic welding
equipment), it shall conform to relevant IEC standard.
7.10.
For welding in an environment with increased hazard of electric shock, see
60974-9 © IEC:2010(E) – 9 –
4.3 Welding circuit
4.3.1 Isolation from the input supply
The welding circuit and circuits electrically connected to the welding circuit shall be electrically
isolated from the mains supply.
Verification shall be carried out by an expert.
4.3.2 Summation of no-load voltages
If more than one welding power source is in use at the same time, their no-load voltages can
be cumulative and could create an increased hazard of electric shock. Welding power sources
shall be installed so as to minimize this risk. Guidance is given in 7.9.
NOTE 1 In the case of two welding transformers connected to the same lines, the resulting output voltage may be
the sum of both no-load voltages. This can be avoided by using a suitable input or output connection (see 7. 9).
NOTE 2 Where more than one welding power source is installed, individual welding power sources with their
separate controls and connections should be clearly identified to show which items belong to any one welding
circuit.
4.3.3 Welding cables
Welding cables shall comply with IEC 60245-6. Copper conductor welding cables shall be
selected in accordance with duty cycle and national regulations or, when not existing, current
rating given in Table 1. Where long cable runs are involved, it may be necessary to choose the
cable size on the basis of voltage drop, see Annex B.
Table 1 – Current ratings for copper welding cables
Current ratings for specified duty cycle at an ambient temperature
a
Nominal cross-
of 25 °C
sectional area
100 % 85 % 80 % 60 % 35 % 20 % 8 %
mm A A A A A A A
10 100 100 100 101 106 118 158
16 135 136 136 139 150 174 243
25 180 182 183 190 213 254 366
35 225 229 231 243 279 338 497
50 285 293 296 316 371 457 681
70 355 367 373 403 482 602 908
95 430 448 456 498 606 765 1 164
120 500 524 534 587 721 917 1 404
150 580 610 622 689 853 1 090 1 676
185 665 702 717 797 995 1 277 1 971
a
For higher ambient temperatures, a correction factor shall be applied:
0,96 (30 °C) ; 0,91 (35 °C) ; 0,87 (40 °C) ; 0,82 (45 °C).
4.3.4 Connection between the welding power source and the workpiece
When the welding current does not flow entirely in the welding circuit, stray currents, which are
components of the welding current, occur. These can cause damage and may be eliminated by
the following means:
– 10 – 60974-9 © IEC:2010(E)
a) the electrical connection between the welding power source and the workpieces shall be
made as direct as practicable by means of an insulated return cable having an adequate
current carrying capacity;
b) extraneous conductive parts, such as metal rails, pipes and frames shall not be used as
part of the welding circuit, unless they constitute the workpiece itself;
c) the return clamp shall be as near as practicable to the welding arc;
NOTE 1 When the return clamp is removed, it should be electrically isolated from parts connected to earth,
e.g. metallic enclosures with protective earth connection (class I), metal floors, building services.
d) the welding circuit shall not be earthed unless required by national or local regulations (see
4.3.5) ;
e) connection of the return cable to the workpiece shall be ensured by the use of devices
having suitable means for cable connection, a fastening system not liable to come loose
accidentally, and good electrical contact. Magnetic devices only present a good electrical
contact if the contact surfaces of the magnetic device and the contact area of the workpiece
are sufficiently large, even, conductive and clean (e.g. free from rust and primer) and if the
contact area of the workpiece is magnetic;
NOTE 2 If workpieces are on a welding bench or a work-handling device, the return cable may be connected
to the bench or device.
f) connection devices for non-stationary flexible welding cables in the welding circuit shall:
1) have an adequate covering of insulating material to prevent inadvertent contact with live
parts, when connected, with the exception of the return clamp at the workpiece itself;
2) be suitable for the sizes of cables used and the welding current;
3) be effectively connected to the welding cables and in good electrical contact with them.
Both the welding cable and the connection device shall be used within their specified current
rating. The connection device shall not be fitted with a cable smaller in diameter than specified
by the manufacturer of the connection device.
When coupling devices are used, they shall comply with IEC 60974-12.
4.3.5 Earthing of the workpiece
The welding circuit should not be earthed, since it can increase the risk of stray welding
currents (see 4.3.3). Earthing of the welding circuit can also increase the area of metal through
which a person in contact with the welding circuit (e.g. the welding electrode) could receive a
shock.
NOTE 1 There are workpieces which have an inherent connection to earth, e.g. steel structures, ships, pipelines
etc. When these are welded, the possibility of stray currents is increased.
NOTE 2 In some cases the workpiece may be in permanent contact with earth, e.g. with protection class I
equipment which itself has protective conductors connected to earth. Such a workpiece is considered to be
inherently connected to earth.
An assessment of the welding circuit and the welding area shall be made to ensure that stray
welding current will not flow through any object connected to earth and not intended or capable
of carrying the welding current (e.g. protective earth connection).
If electrical hand-tools are used, which may come into contact with the workpiece, then those
tools shall be class II equipment (i.e. with double or reinforced insulation without protective
earth connection).
If earthing is required by national or local regulations, the earth connection shall be made by a
separate dedicated cable or conductor with a rating of at least that of the return cable and
connected directly to the workpiece.
60974-9 © IEC:2010(E) – 11 –
Precautions shall be taken to insulate the operator from earth as well as from the workpiece
(see 7.7.2) .
NOTE 3 Where external radio frequency suppression networks are connected to the welding circuit, an expert
should assess whether the welding circuit can still be regarded as insulated from earth.
NOTE 4 External radio frequency suppression networks could consist of a number of different components e.g.
LCR filters (inductance/capacitance/resistance).
4.3.6 Location of gas cylinders
Care shall be taken to prevent gas cylinders in the vicinity of the workpiece becoming part of
the welding circuit.
5 Electromagnetic compatibility (EMC)
5.1 General
The user is responsible for installing and using the arc welding equipment in accordance with
the manufacturer’s instructions. If electromagnetic disturbances are detected, then it shall be
the responsibility of the user of the arc welding equipment to resolve the situation with the
technical assistance of the manufacturer.
5.2 Assessment of area
Before installing arc welding equipment, the user shall make an assessment of potential
electromagnetic interferences in the surrounding area. The following shall be taken into
account:
a) other supply cables, control cables, signalling and telephone cables, above, below and
adjacent to the arc welding equipment;
b) radio and television transmitters and receivers;
c) computer and other control equipment;
d) safety critical equipment, for example guarding of industrial equipment;
e) the health of the people around, for example the use of pacemakers and hearing aids;
f) equipment used for calibration or measurement;
g) the immunity of other equipment in the environment. The user shall ensure that other
equipment being used in the environment is compatible. This may require additional
protection measures;
h) the time of day that welding or other activities are to be carried out.
The size of the surrounding area to be considered will depend on the structure of the building
and other activities that are taking place. The surrounding area may extend beyond the
boundaries of the premises.
5.3 Methods of reducing emissions
5.3.1 Public supply system
The arc weldi
...
IEC 60974-9 ®
Edition 1.0 2010-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Arc welding equipment –
Part 9: Installation and use
Matériel de soudage à l’arc –
Partie 9: Installation et utilisation
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
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International Standards for all electrical, electronic and related technologies.
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IEC 60974-9 ®
Edition 1.0 2010-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Arc welding equipment –
Part 9: Installation and use
Matériel de soudage à l’arc –
Partie 9: Installation et utilisation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
U
CODE PRIX
ICS 25.160.30 ISBN 978-2-88910-364-5
– 2 – 60974-9 © IEC:2010
CONTENTS
FOREWORD.4
1 Scope.6
2 Normative references.6
3 Terms and definitions .6
4 Installation.8
4.1 General .8
4.2 Supply circuit.8
4.2.1 Selection of supply cables.8
4.2.2 Supply disconnecting device .8
4.2.3 Emergency stopping device.8
4.3 Welding circuit.9
4.3.1 Isolation from the input supply.9
4.3.2 Summation of no-load voltages .9
4.3.3 Welding cables .9
4.3.4 Connection between the welding power source and the workpiece.9
4.3.5 Earthing of the workpiece.10
4.3.6 Location of gas cylinders.11
5 Electromagnetic compatibility (EMC) .11
5.1 General .11
5.2 Assessment of area.11
5.3 Methods of reducing emissions .11
5.3.1 Public supply system.11
5.3.2 Maintenance of arc welding equipment.12
5.3.3 Welding cables .12
5.3.4 Equipotential bonding.12
5.3.5 Earthing of the workpiece.12
5.3.6 Screening and shielding.12
6 Electromagnetic fields (EMF) .12
7 Use .13
7.1 General requirements .13
7.2 Connection between several welding power sources .13
7.3 Inspection and maintenance of the welding installation.13
7.3.1 Periodical inspection.13
7.3.2 Routine inspection .13
7.4 Disconnection of welding power sources and/or welding circuits .14
7.5 Guards .14
7.6 Information for operators .14
7.7 Protective measures .14
7.7.1 Extraneous conductive parts in the welding area .14
7.7.2 Protection against electric shock .14
7.8 Isolation of the welding circuit from the workpiece and earth when not in use .14
7.9 Voltage between electrode holders or torches .15
7.10 Welding in an environment with increased hazard of electric shock .17
7.11 Use of shoulder slings .17
7.12 Welding at elevated positions .18
60974-9 © IEC:2010 – 3 –
7.13 Welding with suspended welding equipment.18
Annex A (informative) Hazards associated with arc welding .19
Annex B (informative) Voltage drops in the welding circuit .25
Bibliography .27
Figure 1 – Example of d.c. voltage between electrode holders or torches.15
Figure 2 – Example of a.c. voltage between electrode holders or torches – Single-phase
supply from the same pair of lines of a three-phase mains supply .16
Figure 3 – Example of a.c. voltage between electrode holders or torches – Single-phase
supply from different pairs of lines of a three-phase mains supply.16
Figure 4 – Example of a.c. voltage between electrode holders connected between
different lines of output.17
Figure A.1 – Steps for the control of welding fume .22
Figure A.2 – Steps of operation for work in confined spaces .24
Figure B.1 – Example of MIG/MAG equipment.25
Table 1 – Current ratings for copper welding cables.9
Table B.1 – Voltage drop in copper and aluminium welding cables at normal and
elevated temperatures.26
– 4 – 60974-9 © IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ARC WELDING EQUIPMENT –
Part 9: Installation and use
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
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
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60974-9 has been prepared by IEC technical committee 26: Electric
welding.
This standard cancels and replaces IEC/TS 62081, published in 1999. This first edition
constitutes a technical revision. The following major differences with respect to
IEC/TS 62081:1999 are to be noted:
• 4.3.3 Welding cables: now dimensions are recommended.
• 5 Electromagnetic compatibility (EMC): this is completely new.
• 6 Electromagnetic fields (EMF) : this is completely new.
• 7.3 Inspection and maintenance of the welding installation: there is now a differentiation
between periodical and routine inspection.
60974-9 © IEC:2010 – 5 –
This bilingual version, published in 2010-03, corresponds to the English version.
The text of this part of IEC 60974 is based on the following documents:
FDIS Report on voting
26/404/FDIS 26/405/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 60974 series, under the general title Arc 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 result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – 60974-9 © IEC:2010
ARC WELDING EQUIPMENT –
Part 9: Installation and use
1 Scope
This part of IEC 60974 is applicable to the installation and use of equipment for arc welding
and allied processes designed in accordance with safety requirements of IEC 60974-1,
IEC 60974-6 or equivalent.
This part of IEC 60974 is applicable for the guidance of instructors, operators, welders,
managers, and supervisors in the safe installation and use of equipment for arc welding and
allied processes and the safe performance of welding and cutting operations.
National and local regulations take precedence over this part of IEC 60974.
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60245-6, Rubber insulated cables – Rated voltages up to and including 450/750 V – Part 6:
Arc welding electrode cables
IEC/TR 60755, General requirements for residual current operated protective devices
IEC 60974-1:2005, Arc welding equipment – Part 1: Welding power sources
IEC 60974-4, Arc welding equipment – Part 4: In-service inspection and testing
IEC 60974-6, Arc welding equipment – Part 6: Limited duty manual metal arc welding power
sources
IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC)
requirements
IEC 60974-11, Arc welding equipment – Part 11: Electrode holders
IEC 60974-12, Arc welding equipment – Part 12: Coupling devices for welding cables
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
welding circuit
circuit that includes all conductive material through which the welding current is intended to
flow
60974-9 © IEC:2010 – 7 –
NOTE 1 In arc welding, the arc is a part of the welding circuit.
NOTE 2 In certain arc welding processes, the arc may be established between two electrodes. In such a case, the
workpiece is not necessarily a part of the welding circuit.
[IEC 60974-1:2005, 3.11]
3.2
extraneous conductive part
conductive part not forming part of the electrical installation and liable to introduce an electric
potential, generally the earth potential
NOTE Electrical installation includes the welding circuit.
3.3
workpiece
metal piece or pieces on which welding or allied processes are performed
3.4
protective clothing and accessories
protective clothing and accessories (e.g. gloves, hand shields, head masks and filter lenses)
used in order to diminish electric shock risks and the effects of fume and spatter and to protect
the skin and eyes against arc radiation
3.5
environments with increased hazard of electric shock
environments where the hazard of electric shock by arc welding is increased in relation to
normal arc welding conditions
NOTE 1 Such environments are found for example
a) in locations in which freedom of movement is restricted, so that the operator is forced to perform the welding in
a cramped (for example kneeling, sitting, lying) position with physical contact with conductive parts;
b) in locations which are fully or partially limited by conductive elements and in which there is a high risk of
unavoidable or accidental contact by the operator;
c) in wet, damp or hot locations where humidity or perspiration considerably reduces the skin resistance of the
human body and the insulating properties of accessories.
NOTE 2 Environments with increased hazard of electric shock are not meant to include places where electrically
conductive parts in the near vicinity of the operator which can cause increased hazard have been insulated.
[IEC 60974-1:2005, 3.46]
3.6
industrial and professional use
use intended only for experts or instructed persons
[IEC 60974-1:2005, 3.2]
3.7
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 Several years of practice in the relevant technical field may be taken into consideration in assessment of
professional training.
[IEC 60974-1:2005, 3.3]
– 8 – 60974-9 © IEC:2010
3.8
wire feeder
equipment that delivers filler wire to the arc or weld zone which includes the wire-feed control
and means to apply motion to the filler wire and may also include the filler wire supply
[IEC 60974-5:2007, 3.11]
3.9
auxiliary power output
circuit of a welding power source designed to provide electrical power to auxiliary equipment
4 Installation
4.1 General
Welding equipment used in arc welding installations shall be intended for the purpose and shall
be built in accordance with IEC 60974-1, IEC 60974-4, IEC 60974-6, IEC 60974-10, IEC 60974-
11 and IEC 60974-12 (see Clause 2), as given on the rating plate.
Electromagnetic compatibility (EMC) requirements shall be taken into consideration during
installation, see Clause 5.
The requirements of national and local regulations shall be taken into consideration during
installation, including grounding or protective earth connections, fuses, supply disconnecting
device, type of supply circuit, etc.
Read the manufacturers’ instruction manual before installing the equipment. Full use shall be
made of the technical information relevant to the welding equipment.
Specific advice may be obtained from the welding equipment manufacturer if necessary.
4.2 Supply circuit
4.2.1 Selection of supply cables
Supply cables for welding equipment and their overload protection, if not provided by the
manufacturer, shall be selected in accordance with the information given in the manufacturers’
instruction manual.
Supply cables shall be placed, so that they cannot be damaged in use. If that cannot be
achieved, a sensitive residual current circuit breaker, capable of operating at a leakage current
not exceeding 30 mA in accordance with IEC/TR 60755 shall be used to reduce the risk of
electric shock.
4.2.2 Supply disconnecting device
The installer shall ensure that a supply disconnecting device is fitted at the point of supply.
NOTE A plug may be used as supply disconnecting device in accordance with national or local regulation.
4.2.3 Emergency stopping device
When an emergency stopping device is required by national regulation (e.g. automatic welding
equipment), it shall conform to relevant IEC standard.
7.10.
For welding in an environment with increased hazard of electric shock, see
60974-9 © IEC:2010 – 9 –
4.3 Welding circuit
4.3.1 Isolation from the input supply
The welding circuit and circuits electrically connected to the welding circuit shall be electrically
isolated from the mains supply.
Verification shall be carried out by an expert.
4.3.2 Summation of no-load voltages
If more than one welding power source is in use at the same time, their no-load voltages can
be cumulative and could create an increased hazard of electric shock. Welding power sources
shall be installed so as to minimize this risk. Guidance is given in 7.9.
NOTE 1 In the case of two welding transformers connected to the same lines, the resulting output voltage may be
the sum of both no-load voltages. This can be avoided by using a suitable input or output connection (see 7. 9).
NOTE 2 Where more than one welding power source is installed, individual welding power sources with their
separate controls and connections should be clearly identified to show which items belong to any one welding
circuit.
4.3.3 Welding cables
Welding cables shall comply with IEC 60245-6. Copper conductor welding cables shall be
selected in accordance with duty cycle and national regulations or, when not existing, current
rating given in Table 1. Where long cable runs are involved, it may be necessary to choose the
cable size on the basis of voltage drop, see Annex B.
Table 1 – Current ratings for copper welding cables
Current ratings for specified duty cycle at an ambient temperature
a
Nominal cross-
of 25 °C
sectional area
100 % 85 % 80 % 60 % 35 % 20 % 8 %
mm A A A A A A A
10 100 100 100 101 106 118 158
16 135 136 136 139 150 174 243
25 180 182 183 190 213 254 366
35 225 229 231 243 279 338 497
50 285 293 296 316 371 457 681
70 355 367 373 403 482 602 908
95 430 448 456 498 606 765 1 164
120 500 524 534 587 721 917 1 404
150 580 610 622 689 853 1 090 1 676
185 665 702 717 797 995 1 277 1 971
a
For higher ambient temperatures, a correction factor shall be applied:
0,96 (30 °C) ; 0,91 (35 °C) ; 0,87 (40 °C) ; 0,82 (45 °C).
4.3.4 Connection between the welding power source and the workpiece
When the welding current does not flow entirely in the welding circuit, stray currents, which are
components of the welding current, occur. These can cause damage and may be eliminated by
the following means:
– 10 – 60974-9 © IEC:2010
a) the electrical connection between the welding power source and the workpieces shall be
made as direct as practicable by means of an insulated return cable having an adequate
current carrying capacity;
b) extraneous conductive parts, such as metal rails, pipes and frames shall not be used as
part of the welding circuit, unless they constitute the workpiece itself;
c) the return clamp shall be as near as practicable to the welding arc;
NOTE 1 When the return clamp is removed, it should be electrically isolated from parts connected to earth,
e.g. metallic enclosures with protective earth connection (class I), metal floors, building services.
d) the welding circuit shall not be earthed unless required by national or local regulations (see
4.3.5) ;
e) connection of the return cable to the workpiece shall be ensured by the use of devices
having suitable means for cable connection, a fastening system not liable to come loose
accidentally, and good electrical contact. Magnetic devices only present a good electrical
contact if the contact surfaces of the magnetic device and the contact area of the workpiece
are sufficiently large, even, conductive and clean (e.g. free from rust and primer) and if the
contact area of the workpiece is magnetic;
NOTE 2 If workpieces are on a welding bench or a work-handling device, the return cable may be connected
to the bench or device.
f) connection devices for non-stationary flexible welding cables in the welding circuit shall:
1) have an adequate covering of insulating material to prevent inadvertent contact with live
parts, when connected, with the exception of the return clamp at the workpiece itself;
2) be suitable for the sizes of cables used and the welding current;
3) be effectively connected to the welding cables and in good electrical contact with them.
Both the welding cable and the connection device shall be used within their specified current
rating. The connection device shall not be fitted with a cable smaller in diameter than specified
by the manufacturer of the connection device.
When coupling devices are used, they shall comply with IEC 60974-12.
4.3.5 Earthing of the workpiece
The welding circuit should not be earthed, since it can increase the risk of stray welding
currents (see 4.3.3). Earthing of the welding circuit can also increase the area of metal through
which a person in contact with the welding circuit (e.g. the welding electrode) could receive a
shock.
NOTE 1 There are workpieces which have an inherent connection to earth, e.g. steel structures, ships, pipelines
etc. When these are welded, the possibility of stray currents is increased.
NOTE 2 In some cases, the workpiece may be in permanent contact with earth, e.g. with protection class I
equipment which itself has protective conductors connected to earth. Such a workpiece is considered to be
inherently connected to earth.
An assessment of the welding circuit and the welding area shall be made to ensure that stray
welding current will not flow through any object connected to earth and not intended or capable
of carrying the welding current (e.g. protective earth connection).
If electrical hand-tools are used, which may come into contact with the workpiece, then those
tools shall be class II equipment (i.e. with double or reinforced insulation without protective
earth connection).
If earthing is required by national or local regulations, the earth connection shall be made by a
separate dedicated cable or conductor with a rating of at least that of the return cable and
connected directly to the workpiece.
60974-9 © IEC:2010 – 11 –
Precautions shall be taken to insulate the operator from earth as well as from the workpiece
(see 7.7.2) .
NOTE 3 Where external radio frequency suppression networks are connected to the welding circuit, an expert
should assess whether the welding circuit can still be regarded as insulated from earth.
NOTE 4 External radio frequency suppression networks could consist of a number of different components e.g.
LCR filters (inductance/capacitance/resistance).
4.3.6 Location of gas cylinders
Care shall be taken to prevent gas cylinders in the vicinity of the workpiece becoming part of
the welding circuit.
5 Electromagnetic compatibility (EMC)
5.1 General
The user is responsible for installing and using the arc welding equipment in accordance with
the manufacturer’s instructions. If electromagnetic disturbances are detected, then it shall be
the responsibility of the user of the arc welding equipment to resolve the situation with the
technical assistance of the manufacturer.
5.2 Assessment of area
Before installing arc welding equipment, the user shall make an assessment of potential
electromagnetic interferences in the surrounding area. The following shall be taken into
account:
a) other supply cables, control cables, signalling and telephone cables, above, below and
adjacent to the arc welding equipment;
b) radio and television transmitters and receivers;
c) computer and other control equipment;
d) safety critical equipment, for example guarding of industrial equipment;
e) the health of the people around, for example the use of pacemakers and hearing aids;
f) equipment used for calibration or measurement;
g) the immunity of other equipment in the environment. The user shall ensure that other
equipment being used in the environment is compatible. This may require additional
protection measures;
h) the time of day that welding or other activities are to be carried out.
The size of the surrounding area to be considered will depend on the structure of the building
and other activities that are taking place. The surrounding area may extend beyond the
boundaries of the premises.
5.3 Methods of reducing emissions
5.3.1 Public supply system
The arc welding equipment shall be connected to the public supply system in accordance with
the manufacturer’s recommendations. If interference occurs, it may be necessary to take
additional precautions such as filtering of the supply system. Consideration shall be given to
shielding the supply cable of permanently installed arc welding equipment, in metallic conduit
or equivalent. Shielding shall be electrically continuous throughout its length. The shielding
shall be connected to the welding power source so that good electrical contact is maintained
between the conduit and the welding power source enclosure.
– 12 – 60974-9 © IEC:2010
5.3.2 Maintenance of arc welding equipment
The arc welding equipment shall be routinely maintained in accordance with IEC 60974-4 and
the manufacturer’s instructions. All access and service doors and covers shall be closed and
properly fastened when the arc welding equipment is in operation. The arc welding equipment
shall not be modified in any way, except for those changes and adjustments covered in the
manufacturer’s instructions. In particular, the spark gaps of arc striking and stabilising devices
shall be adjusted and maintained in accordance with the manufacturer’s instructions.
5.3.3 Welding cables
The welding cables shall be kept as short as possible and shall be positioned as close as
possible to each other, running at or close to the floor level. The welding cables shall never be
coiled.
5.3.4 Equipotential bonding
Bonding of all metallic objects in the surrounding area should be considered for the purpose of
reducing emissions. However, metallic objects bonded to the workpiece will increase the risk
that the operator could receive an electric shock by touching these metallic objects and the
electrode at the same time. The operator shall be insulated from all such bonded metallic
objects.
5.3.5 Earthing of the workpiece
Where the workpiece is not bonded to earth for electrical safety, a connection bonding the
workpiece to earth may reduce emissions in some, but not all instances. Care should be taken
to prevent the earthing of the workpiece increasing the risk of injury to users, or damage to
other electrical equipment. Where necessary, the connection of the workpiece to earth should
be made by a direct connection to the workpiece, but in some countries where direct
connection is not permitted, the bonding should be achieved by suitable capacitance, selected
in accordance with national and local regulations.
5.3.6 Screening and shielding
Selective screening and shielding of other cables and equipment in the surrounding area may
alleviate problems of interference. Screening of the entire welding area may be considered for
special applications.
6 Electromagnetic fields (EMF)
Electric current flowing through any conductor causes localized electric and magnetic fields
(EMF). All welders should use the following procedures in order to minimize the risk associated
with exposure to EMF from the welding circuit:
– route the welding cables together – secure them with tape when possible;
– place your torso and head as far away as possible from the welding circuit;
– never coil welding cables around your body;
– do not place your body between welding cables. Keep both welding cables on the same
side of your body;
– connect the return cable to the workpiece as close as possible to the area being welded;
– do not work next to, sit or lean on the welding power source;
– do not weld whilst carrying the welding power source or wire feeder.
EMF may also interfere with medical implants, e.g. pacemakers. Protective measures for
persons with medical implants shall be taken. For example, access restrictions for passers-by
60974-9 © IEC:2010 – 13 –
or individual risk-evaluations for welders. Risk assessment and recommendation for users of
medical implants shall be made by a medical expert.
7 Use
7.1 General requirements
User shall ensure that arc welding equipment and accessories conform to the relevant parts of
IEC 60974, see Clause 2, as given on the rating plate. Before welding equipment is put into
service, the user shall read and understand the instructions provided by the manufacturer,
national or local regulation, trade association and occupational recommendations, national
health and safety recommendations.
Consideration shall be given to the environment in which the welding equipment is used as
additional precautions may need to be taken e.g. increased hazard of electric shock; confined
spaces; flammable area, asphyxiation (see Annex A).
7.2 Connection between several welding power sources
If welding power sources are to be connected in parallel or in series, this shall be carried out by
an expert and in accordance with the manufacturers' recommendations. The equipment shall
be approved for arc welding operations only after a check has been carried out to ensure that
the permissible no-load voltage cannot be exceeded.
When one welding power source connected in parallel or series is taken out of service, that
power source shall be disconnected from the mains supply and from the welding circuit, so as
to prevent any hazards that might be caused by feed-back voltages.
7.3 Inspection and maintenance of the welding installation
7.3.1 Periodical inspection
On installation, and periodically thereafter, an expert nominated for the task shall check that
the welding equipment has been correctly selected and connected for the work to be carried
out in accordance with IEC 60974-4 and the manufacturer's instructions and that all
connections are clean and tight and the welding equipment is in good condition.
In addition, all protective earthing shall be checked for effectiveness. Any defects found shall
be repaired.
7.3.2 Routine inspection
The operator shall be instructed to check all external connections daily and each time a
reconnection is made. Particular attention shall be paid to the installation of supply and welding
cables, electrode holders and coupling devices. Any defects found shall be reported, and faulty
equipment shall not be used until it has been repaired.
The return clamp shall be connected directly to the workpiece as close as practicable to the
point of welding or to the welding bench on which the workpiece is situated or to the work-
handling device.
For plasma cutting the no-load voltages are higher than with welding. This shall be considered
during inspection and maintenance procedures. Particular attention shall be paid to the water
cooling equipment to ensure that any leaks do not affect the insulation.
– 14 – 60974-9 © IEC:2010
Before carrying out arc welding on equipment having associated transformers (e.g. arc
furnaces), such transformers shall be isolated to avoid the hazard of shock from induced
voltages on the input side of the transformer.
7.4 Disconnection of welding power sources and/or welding circuits
If the supply cable or the welding cables are liable to damage when the welding power source
is moved to another location, that power source, including its cables, shall be disconnected
before it is moved.
When maintenance or repair work is carried out on the welding equipment, the input and output
shall be disconnected.
7.5 Guards
Guards and removable parts of the enclosure shall be in position before the welding equipment
is made live.
7.6 Information for operators
Operators and their assistants shall be trained in the safe use of equipment. Operators and
persons working in the vicinity of the welding operation shall be warned of the hazards and
informed about protective measures concerning arc processes (see Annex A).
The operator shall prevent gas cylinders in the vicinity of the workpiece from becoming part of
the welding circuit.
7.7 Protective measures
7.7.1 Extraneous conductive parts in the welding area
With respect to extraneous conductive parts,
a) persons shall be aware of such parts, see 3.2;
b) care shall be taken to minimize the extent of such parts;
c) torches and electrode holders shall be kept insulated from extraneous conductive parts in
the welding area.
7.7.2 Protection against electric shock
The operator shall take precautions to be insulated from the electrode, the workpiece and
conductive parts in contact with earth in the vicinity. This can normally be achieved with dry
gloves, clothing, head gear, footwear, dry boards and insulating mats or similar in good
condition. An expert shall assess whether the proposed insulation method is suitable.
NOTE An operator, who comes into direct contact with both terminals of the welding power source, or conductors
connected to them, may experience an electric shock. Under some circumstances, the electric shock may be
severe enough to cause injury or death.
7.8 Isolation of the welding circuit from the workpiece and earth when not in use
When not in use (e.g. during lunch or changing shift), electrode holders and torch circuits shall,
where practicable, be switched off at the welding power source; if this is not possible, they shall
be kept isolated and/or be insulated, without contact with the workpiece or other conductive
parts, especially the welding power source enclosures. Manual metal arc welding electrodes
shall be removed from the electrode holder when the welding operation has been completed. If
applicable, shielding gas supply shall be closed.
60974-9 © IEC:2010 – 15 –
The operator shall ensure that the return current clamp is either connected to the workpiece or
stored isolated from earth or any conductive part.
7.9 Voltage between electrode holders or torches
When working with several welding power sources on a single workpiece or on conductively
connected workpieces, a hazardous sum of no-load voltages may arise between two
electrode holders or torches. This may reach twice the value of the admissible no-load voltage
(see also 4.3.2) .
The instructed person who is co-ordinating the welding tasks shall ensure that a measuring
device is used to determine whether there is a hazard.
Operators shall:
a) be warned of this hazard;
b) never touch two electrode holders or torches at the same time;
c) work out of reach of each other, where practicable.
The following examples show schematically the influence that the connection to the mains
supply and the polarity for welding may have on the sum of welding voltages between electrode
holders or torches. It is assumed that the no-load voltages for each welding power source are
identical but in practice they may differ (see items a) to c) below).
a) Direct current
The connections to the mains supply have no influence on the sum of no-load voltages. The
voltage U depends on the polarity of the output connections (see Figure 1).
U = 2U
U = 0
IEC 582/99
NOTE The polarity for welding depends on the welding process.
Figure 1 – Example of d.c. voltage between electrode holders or torches
– 16 – 60974-9 © IEC:2010
b) Alternating current single-phase welding power sources
The connections to the mains supply and the output connections will influence the sum U of
the no-load voltages (see Figure 2).
L1
L2
U=2U U=2U U=0
o o
U=0
IEC 583/99
Figure 2 – Example of a.c. voltage between elect
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