IEC 60974-2:2013

Arc welding equipment - Part 2: Liquid cooling systems

IEC 60974-2:2013 specifies safety and construction requirements for industrial and professional liquid cooling systems used in arc welding and allied processes to cool torches. This part of IEC 60974 is applicable to stand-alone liquid cooling systems that are either connected to a separate welding power source or built into the welding power source enclosure. This part of IEC 60974 is not applicable to refrigerated cooling systems. This third edition cancels and replaces the first edition published in 2007 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- changes induced by the publication of IEC 60974-1:2012;
- addition of a liquid temperature fixed to 65 °C during the heating test in order to allow testing at different ambient air temperature (see 10 d));
- correction factor of cooling power at 40 °C required in instruction manual (see 12.1 o)).
This publication is to be read in conjunction with IEC 60974-1:2012.

Matériel de soudage à l'arc - Partie 2: Systèmes de refroidissement par liquide

La CEI 60974-2:2013 spécifie les exigences de sécurité et de construction des systèmes de refroidissement par liquide industriels et professionnels utilisés en soudage à l'arc et techniques connexes pour refroidir des torches. La présente partie de la CEI 60974 s'applique aux systèmes de refroidissement par liquide indépendants qui sont soit raccordés à une source de courant de soudage séparée soit incorporés dans l'enveloppe de la source de courant de soudage. La présente partie de la CEI 60974 ne s'applique pas aux systèmes de refroidissement avec réfrigération. Cette troisième édition annule et remplace la seconde édition parue en 2007 et constitue une révision technique. Les modifications techniques majeures par rapport à l'édition précédente sont les suivantes:
- modifications induites par la publication de la CEI 60974-1:2012;
- addition d'une température du liquide fixée à 65 °C pendant l'essai d'échauffement afin de permettre les essais à différentes températures ambiantes (voir 10 d));
- facteur de correction de la puissance de refroidissement à 40 °C requis dans le manuel d'instructions (voir 12.1 o)).
Cette publication doit être lue conjointement avec la CEI 60974-1:2012.

General Information

• Status: Published
• Publication Date: 23-Jan-2013
• 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: 28-Apr-2017
• Completion Date: 30-Jan-2019

Relations

• Revised: IEC 60974-2:2019 - Arc welding equipment - Part 2: Liquid cooling systems
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60974-2


®


Edition 3.0 2013-01



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE


Arc welding equipment –
Part 2: Liquid cooling systems

Matériel de soudage à l’arc –
Partie 2: Systèmes de refroidissement par liquide



IEC 60974-2:2013

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IEC 60974-2



®



Edition 3.0 2013-01







INTERNATIONAL





STANDARD







NORME



INTERNATIONALE











Arc welding equipment –

Part 2: Liquid cooling systems




Matériel de soudage à l’arc –

Partie 2: Systèmes de refroidissement par liquide

















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX R


ICS 25.160 ISBN 978-2-83220-572-3



Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

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

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CONTENTS

FOREWORD . 4


1 Scope . 6

2 Normative references . 6

3 Terms and definitions . 6


4 Environmental conditions . 7

5 Tests . 7

5.1 Test conditions . 7

5.2 Measuring instruments . 7
5.3 Conformity of components . 7
5.4 Type tests . 7
5.5 Routine tests . 7
6 Protection against electric shock . 8
6.1 Insulation . 8
6.1.1 General . 8
6.1.2 Clearances . 8
6.1.3 Creepage distances . 8
6.1.4 Insulation resistance . 8
6.1.5 Dielectric strength . 8
6.2 Protection against electric shock in normal service (direct contact) . 8
6.3 Protection against electric shock in case of a fault condition (indirect contact) . 8
6.3.1 Protective provisions . 8
6.3.2 Isolation between windings of the supply circuit and the welding
circuit . 8
6.3.3 Internal conductors and connections . 8
6.3.4 Touch current in fault condition . 8
6.4 Connection to the supply network . 8
6.4.1 Supply voltage . 8
6.4.2 Multi-supply voltage . 8
6.4.3 Means of connection to the supply circuit . 9
6.4.4 Marking of terminals . 9
6.4.5 Protective circuit . 9
6.4.6 Cable anchorage . 9

6.4.7 Inlet openings . 9
6.4.8 Supply circuit on/off switching device . 9
6.4.9 Supply cables . 9
6.4.10 Supply coupling device (attachment plug) . 9
6.5 Leakage current between welding circuit and protective earth . 9
7 Mechanical provisions . 10
7.1 General . 10
7.2 Cooling liquid overflow . 10
7.3 Hose coupling devices and hose connections . 10
8 Cooling system . 10
8.1 Rated maximum pressure . 10
8.2 Thermal requirements . 11
8.2.1 Heating test . 11
8.2.2 Tolerances of test parameters . 11

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60974-2 © IEC:2013 – 3 –


8.2.3 Duration of test . 11

8.3 Pressure and temperature . 11

9 Abnormal operation . 11


9.1 General requirements . 11

9.2 Stalled test . 11

10 Cooling power . 12

11 Rating plate . 13


11.1 General . 13

11.2 Description . 13

11.3 Contents. 14
11.4 Tolerances . 15
12 Instructions and markings . 15
12.1 Instructions . 15
12.2 Markings . 15
12.2.1 General . 15
12.2.2 Inlet and outlet . 15
12.2.3 Pressure warning . 16
Annex A (informative) Example diagram of built-in and stand-alone liquid cooling
systems . 17
Annex B (informative) Example for a rating plate of stand-alone cooling system . 18

Figure 1 – Leakage current measurement configuration . 10
Figure 2 – Measuring circuit for determination of the cooling power . 13
Figure 3 – Principle of the rating plate of stand-alone cooling systems . 14
Figure A.1 – Example diagram of built-in liquid cooling systems. 17
Figure A.2 – Example diagram of stand-alone liquid cooling systems . 17

Table 1 – Example of cooling liquid data at 60 °C . 13

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INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________




ARC WELDING EQUIPMENT –



Part 2: Liquid cooling systems



FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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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
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60974-2 has been prepared by IEC technical committee 26:
Electric welding.
This third edition cancels and replaces the first edition published in 2007 and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• changes induced by the publication of IEC 60974-1:2012;
• addition of a liquid temperature fixed to 65 °C during the heating test in order to allow
testing at different ambient air temperature (see 10 d));
• correction factor of cooling power at 40 °C required in instruction manual (see 12.1 o)).

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60974-2 © IEC:2013 – 5 –


The text of this standard is based on the following documents:


FDIS Report on voting

26/494/FDIS 26/496/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.


In this standard, the following print types are used:
– conformity statements: in italic type.
This standard shall be used in conjunction with IEC 60974-1:2012.
The list of all parts of IEC 60974, under the general title Arc welding equipment, can be found
on the IEC web site.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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 2: Liquid cooling systems








1 Scope


This part of IEC 60974 specifies safety and construction requirements for industrial and

professional liquid cooling systems used in arc welding and allied processes to cool torches.
This part of IEC 60974 is applicable to stand-alone liquid cooling systems that are either
connected to a separate welding power source or built into the welding power source
enclosure.
This part of IEC 60974 is not applicable to refrigerated cooling systems.
NOTE 1 Typical allied processes are electric arc cutting and arc spraying.
NOTE 2 This part of IEC 60974 does not include electromagnetic compatibility (EMC) requirements.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60974-1:2012, Arc welding equipment – Part 1: Welding power sources
IEC 60974-7, Arc welding equipment – Part 7: Torches
IEC 60974-10, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC)
requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60974-1 and

IEC 60974-7, as well as the following apply.
3.1
cooling power
P
cooling energy related to the flow rate
3.2
liquid cooling system
system that circulates and cools liquid used for decreasing the temperature of torches
3.3
cooling power at 1 l/min

P
1 l/min
cooling power at 1 l/min flow rate defined for comparison

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60974-2 © IEC:2013 – 7 –


4 Environmental conditions


As specified in Clause 4 of IEC 60974-1:2012.



5 Tests


5.1 Test conditions


As specified in 5.1 of IEC 60974-1:2012.


Stand-alone cooling systems may be tested without a welding power source.
Built-in cooling systems shall be tested with the welding power source.
5.2 Measuring instruments
The accuracy of measuring instruments shall be:
a) electrical measuring instruments: class 1 (± 1 % of full-scale reading), except for the
measurement of insulation resistance and dielectric strength where the accuracy of the
instruments is not specified, but shall be taken into account for the measurement;
b) thermometer: ± 2 K;
c) pressure measuring instruments: class 2,5 (± 2,5 % of full-scale reading);
d) flow-rate measuring instruments: class 2,5 (± 2,5 % of full-scale reading).
5.3 Conformity of components
As specified in 5.3 of IEC 60974-1:2012.
5.4 Type tests
All type tests shall be carried out on the same cooling system unless specified otherwise.
As a condition of conformity the type tests given below shall be carried out in the following
sequence:
a) general visual inspection (as defined in 3.7 of IEC 60974-1:2012);
b) protection provided by the enclosure (as specified in 6.2.1 of IEC 60974-1:2012);
c) mechanical provisions (as specified in Clause 7);

d) insulation resistance (as specified in 6.1.4);
e) dielectric strength (as specified in 6.1.5).
The other tests included in this standard and not listed here may be carried out in any
convenient sequence.
5.5 Routine tests
All routine tests given below shall be carried out on each cooling system in the following
sequence:
a) visual inspection in accordance with manufacturer’s specification;
b) continuity of the protective circuit (as specified in 10.4.2 of IEC 60974-1:2012);
c) dielectric strength (as specified in 6.1.5).

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6 Protection against electric shock


6.1 Insulation


6.1.1 General


As specified in 6.1.1 of IEC 60974-1:2012.


6.1.2 Clearances

As specified in 6.1.2 of IEC 60974-1:2012.

6.1.3 Creepage distances
As specified in 6.1.3 of IEC 60974-1:2012.
6.1.4 Insulation resistance
As specified in 6.1.4 of IEC 60974-1:2012.
The test may be carried out without cooling liquid.
6.1.5 Dielectric strength
As specified in 6.1.5 of IEC 60974-1:2012.
The test may be carried out without cooling liquid.
6.2 Protection against electric shock in normal service (direct contact)
As specified in 6.2 of IEC 60974-1:2012.
6.3 Protection against electric shock in case of a fault condition (indirect contact)
6.3.1 Protective provisions
As specified in 6.3.1 of IEC 60974-1:2012.
6.3.2 Isolation between windings of the supply circuit and the welding circuit
As specified in 6.3.2 of IEC 60974-1:2012.

6.3.3 Internal conductors and connections
As specified in 6.3.3 of IEC 60974-1:2012.
6.3.4 Touch current in fault condition
As specified in 6.3.6 of IEC 60974-1:2012.
6.4 Connection to the supply network
6.4.1 Supply voltage
As specified in 10.1 of IEC 60974-1:2012.
6.4.2 Multi-supply voltage
As specified in 10.2 of IEC 60974-1:2012.

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60974-2 © IEC:2013 – 9 –


6.4.3 Means of connection to the supply circuit


As specified in 10.3 of IEC 60974-1:2012.


6.4.4 Marking of terminals


As specified in 10.4 of IEC 60974-1:2012.


6.4.5 Protective circuit

As specified in 10.5 of IEC 60974-1:2012.


6.4.6 Cable anchorage
As specified in 10.6 of IEC 60974-1:2012.
6.4.7 Inlet openings
As specified in 10.7 of IEC 60974-1:2012.
6.4.8 Supply circuit on/off switching device
As specified in 10.8 of IEC 60974-1:2012.
6.4.9 Supply cables
As specified in 10.9 of IEC 60974-1:2012.
6.4.10 Supply coupling device (attachment plug)
For supply networks up to 125 V, the rated current of the supply coupling device (attachment
plug) shall be not less than 70 % of the supply current, as measured with the fan motor or
pump stalled, whichever is greater.
6.5 Leakage current between welding circuit and protective earth
With the cooling system filled with the cooling liquid specified by the manufacturer
(see 12.1 e)), the leakage current from the torch to the protective earth connection of the
cooling system shall not exceed 10 mA d.c.
Conformity shall be checked by applying a d.c. voltage of 500 V at room temperature between
the protective earth connection and a copper pipe to simulate the torch connected to the
output of the cooling system by a hose with a maximum length of 0,5 m as shown in Figure 1.
The minimum inner diameter of the hose shall be 5 mm. The minimum length of the copper
pipe shall be 10 cm with a minimum internal diameter of 5 mm. The cooling system and the
simulated torch are filled with liquid for the test. The pump is operating.
NOTE The design of the torch can influence the leakage current value; therefore, a conventional copper pipe is
used to simulate the torch during the conformity test.

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0,5 m 0,1 m



2
3



2

1
A




500 V d.c.
IEC  2209/07

Key
1 Liquid cooling system
2 Hose
3 Copper pipe
Figure 1 – Leakage current measurement configuration
7 Mechanical provisions
7.1 General
As specified in Clause 14 of IEC 60974-1:2012.
The test shall be carried out with cooling liquid.
7.2 Cooling liquid overflow
When filling the cooling system in accordance with the manufacturer's instructions, overflow
or spillage shall not result in electric shock.
Conformity shall be checked by the following treatment and test. The liquid container is
completely filled. A further quantity of liquid equal to 15 % of the capacity of the container or
0,25 l, whichever is the greater, is then poured in steadily over a period not to exceed 60 s.
Immediately after this treatment, the equipment shall pass the dielectric strength test of 6.1.5
between input circuits and exposed conductive parts.

7.3 Hose coupling devices and hose connections
If hose coupling devices or hose connections, which often have to be undone, are placed
above or near to live parts, these live parts shall be protected from cooling liquid by splash
proof enclosures, with drains or other appropriate measures. An exception is made for live
parts of the welding circuit.
8 Cooling system
8.1 Rated maximum pressure
The manufacturer shall determine the rated maximum pressure attainable by the cooling
system (see 11.3 c), box 12).
Conformity shall be checked by measuring the pressure when the outlet is blocked.

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60974-2 © IEC:2013 – 11 –


8.2 Thermal requirements


8.2.1 Heating test

Liquid cooling systems shall be capable of operating at rated cooling power without causing
any component to exceed its rated temperature.

Conformity shall be checked in accordance with Clause 10.


8.2.2 Tolerances of test parameters

+10 %
a) p pressure: p

−2 %
+10 %
b) q volume flow:
q
v v
−2 %
c) T temperature: T ± 2 K
8.2.3 Duration of test
As specified in 7.1.3 of IEC 60974-1:2012.
8.3 Pressure and temperature
Liquid cooling systems shall be capable of operating without leakage at the maximum
pressure with a cooling liquid temperature of 70 °C.
Conformity shall be checked by visual inspection during 120 s of operation or until shutdown
by a protection system, immediately following the heating test while the outlet of the cooling
system is blocked.
9 Abnormal operation
9.1 General requirements
A cooling system shall not break down and increase the risk of electric shock or fire, under
the conditions of operation of 9.2. These tests are conducted without regard to temperature
attained on any part, or the continued proper functioning of the cooling system. The only
criterion is that the cooling system does not become unsafe. These tests may be conducted
on any cooling systems that function correctly.
The cooling system, protected internally by, for example, a circuit-breaker or thermal
protection, meets this requirement if the protection device operates before an unsafe

condition occurs.
Conformity shall be checked by the following tests.
a) A layer of dry absorbent surgical type cotton is placed under the cooling system,
extending beyond each side for a distance of 150 mm.
b) Starting fro
...