IEC 60974-9:2010

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


IEC 60974-9:2010

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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
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 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

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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

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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.

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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.

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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

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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]

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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

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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 %
2
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:

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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 case
...