EN 60974-1:2012

FOREWORD
1 Scope
2 Normative references
3 Terms and definitions
4 Environmental conditions
5 Tests
6 Protection against electric shock
7 Thermal requirements
8 Thermal protection
9 Abnormal operation
10 Connection to the supply network
11 Output
12 Control circuits
13 Hazard reducing device
14 Mechanical provisions
15 Rating plate
16 Adjustment of the output
17 Instructions and markings
Annex A (informative) - Nominal voltages of supply networks
Annex B (informative) - Example of a combined dielectric test
Annex C (normative) - Unbalanced load in case of a.c. tungsten
        inert-gas welding power sources
Annex D (informative) - Extrapolation of temperature to time
        of shutdown
Annex E (normative) - Construction of supply circuit terminals
Annex F (informative) - Cross-reference to non-SI units
Annex G (informative) - Suitability of supply network for the
        measurement of the true r.m.s. value of the supply current
Annex H (informative) - Plotting of static characteristics
Annex I (normative) - Test methods for a 10 Nm impact
Annex J (normative) - Thickness of sheet metal for enclosures
Annex K (informative) - Examples of rating plates
Annex L (informative) - Graphical symbols for arc welding equipment
Annex M (informative) - Efficiency
Annex N (normative) - Touch current measurement in fault condition
Bibliography
Annex ZA (normative) - Normative references to international
         publications with their corresponding European
         publications

IEC 60974-1:2012 is applicable to power sources for arc welding and allied processes designed for industrial and professional use, and supplied by a voltage not exceeding 1 000 V, or driven by mechanical means. This part of IEC 60974 specifies safety and performance requirements of welding power sources and plasma cutting systems. This fourth edition cancels and replaces the third edition published in 2005 and constitutes a technical revision. The significant changes with respect to the previous edition are the following: - the heating test shall be carried out at ambient temperature of 40 °C (see 5.1); - new Figure 1 summarizes example of insulation requirements; - creepage distances for pollution degree 4 are no longer valid (see Table 2); - insulation requirements for Class II equipment are defined (see Table 3); - dielectric test voltage interpolation restriction lower limit is changed to 220 V and interpolation for control and welding circuit is clarified (see Table 4); - water test is clarified by suppression of visual inspection (see 6.2.1); - isolation requirements of the supply circuit and the welding circuit are moved in protection against electric shock in normal service (see 6.2.4); - touch current in normal service and in single fault condition requirements are changed (see 6.2.5, 6.2.6 and 6.3.6); - maximum temperature for insulation systems are reviewed in accordance with current edition of IEC 60085 (see Table 6); - limits of temperature rise for external surfaces are updated depending of unintentional contact period as defined in ISO 13732-1 (see Table 7); - loading test is completed by a dielectric test (see 7.4); - conformity test for tolerance to supply voltage fluctuation is clarified (see 10.1); - marking of terminals is limited to external protective conductor and three-phase equipment terminals (see 10.4); - usage of hazard reducing device is clarified (see 11.1); - requirements for control circuits are changed (see Clause 12); - impact test is clarified (see 14.2.2); - environmental parameters are completed (see Annex M).