IEC 60974-1:2021

Overview - IEC 60974-1:2021 (Arc welding equipment - Welding power sources)

IEC 60974-1:2021 is the sixth edition of the international standard for welding power sources used in arc welding and allied processes. It applies to industrial and professional equipment supplied by voltage up to 1 000 V, including battery-powered and mechanically driven power sources. The standard sets out safety and performance requirements for welding power sources and plasma cutting systems and replaces the 2017 edition and its 2019 amendment.

Key updates in the 2021 edition include changes to insulation dimensioning referencing IEC 60664-1:2020, revised touch-current measurement networks (weighted for let‑go / immobilization), new requirements for displayed voltage accuracy, and updated efficiency and idle-power measurement methods aligned with IEC 62301.

Key topics and technical requirements

• Scope & definitions: Detailed terms and definitions (including battery systems and efficiency measures) with a new alphabetical cross‑reference (Table 1).
• Protection against electric shock: Insulation, clearance/creepage distances, touch current limits, and fault‑condition requirements.
• Thermal requirements & protection: Heating tests, temperature-rise limits, overload protection, and thermal cutouts.
• Tests and abnormal operation: Type and routine tests, stalled‑fan, short circuit, overload and capacitor short‑circuit tests (moved to Subclause 9.5).
• Output & control: Rated no‑load voltage, conventional load characteristics, output adjustment and display accuracy (new structure in 16.3).
• Mechanical and electrical construction: Enclosure, terminals, cable anchorage, and supply coupling devices.
• Marking, instructions and rating plate: Mandatory content and tolerances for identification and safe use.
• Annexes: Normative and informative annexes expanded-Annex A became normative; Annex M redrafted for efficiency/idle measurements; Annex N added a measurement network weighted for let‑go/immobilization; Annex O covers battery‑powered sources.

Applications - who uses IEC 60974-1

• Manufacturers of welding and plasma cutting power sources - for design compliance, testing and CE/market entry.
• Test laboratories and certification bodies - to perform type and routine tests and verify safety/performance.
• Safety engineers and compliance officers - to ensure installations meet electrical, thermal and touch‑current standards.
• Procurement and asset managers - to specify compliant equipment for industrial and professional welding operations.
• Design engineers - for component selection, insulation coordination (per IEC 60664‑1) and efficiency optimization.

Related standards

• IEC 60664-1:2020 - insulation coordination, clearance and creepage reference.
• IEC 62301 - energy consumption and idle state power measurement methodology (referenced in Annex M).

Keywords: IEC 60974-1, welding power sources, arc welding equipment, plasma cutting systems, welding safety, touch current, insulation, efficiency measurement, battery-powered welding.