IEC 60974-1:2021 is available as IEC 60974-1:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60974-1:2021 is applicable to power sources for arc welding and allied processes designed for industrial and professional use, and supplied by a voltage not exceeding 1 000 V, battery supplied or driven by mechanical means. This document specifies safety and performance requirements of welding power sources and plasma cutting systems. This sixth edition cancels and replaces the fifth edition published in 2017 and Amendment 1:2019. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:

- Table 1 with an alphabetical cross-reference listing of terms added;

- clearance and creepage distance reference document changed to IEC 60664-1:2020;

- 6.1.2 and 6.1.3 modified to follow IEC 60664-1 basic insulation dimensioning for mains supply with rationalized voltages;

- abnormal capacitor test of 6.2.2 moved to new Subclause 9.5;

- 6.2.5 and 6.3.6 modified to use touch current measuring network weighted for letgo-immobilization and supply voltage tolerance requirement added;

- 16.3 new structure and accuracy requirement for displayed voltage value ;

- Annex A changed to normative and Table A.2 and Table A.3 added;

- Annex L editorial update to standardized symbols;

- redraft of efficiency and idle state power measurement in Annex M based on IEC 62301:2011;

- Annex N measurement network weighted for letgo-immobilization added.