IEC 60851-3:2023

Overview - IEC 60851-3:2023 (Winding wires, Part 3: Mechanical properties)

IEC 60851-3:2023 specifies mechanical test methods for winding wires used in electrical machines and components. This fourth edition (2023) is a technical revision that cancels and replaces the 2009 edition and subsequent amendments. It defines standardized procedures for measuring mechanical performance such as elongation, springiness, flexibility/adherence, abrasion resistance and heat bonding. For definitions and general test notes, IEC 60851-1 applies. Annex B of IEC 60851-3 provides recommended friction test methods.

Key topics and technical requirements

The standard contains clear, test-specific methods and scope conditions. Major topics include:

• Test 6 - Elongation: determination of elongation at fracture and tensile strength for conductor materials.
• Test 7 - Springiness: procedures for assessing wire spring-back; covers round wire (nominal diameters from 0.080 mm up to and including 1.600 mm) and larger/rectangular wire variants.
• Test 8 - Flexibility and adherence: includes mandrel winding tests, stretching, jerk and peel tests; special methods for fibre-covered, tape-wrapped and covered bunched wires. (Jerk test applicable up to and including 1.000 mm; peel test applicable over 1.000 mm.)
• Test 11 - Resistance to abrasion: abrasion test method applicable to enamelled round wire.
• Test 18 - Heat bonding: vertical bond retention and bond strength tests for enamelled round wire (nominal conductor diameter > 0.050 mm up to and including 2.000 mm) and enamelled rectangular wire.
• Annex B - Friction tests: recommended static and dynamic friction test methods (various tests applicable to enamelled round wires, with diameter limits noted in the standard).

Significant editorial/technical change in 2023: clarified distance measurement for determining loss of adhesion for fibre-covered and tape‑wrapped wires.

Practical applications and who uses this standard

IEC 60851-3 is practical for:

• Winding wire manufacturers - to qualify coating systems, bonding and mechanical durability.
• Component OEMs (motors, transformers, inductors, actuators) - for supplier specifications and incoming inspection.
• Independent test laboratories - to run accredited mechanical tests and report standardized results.
• R&D and materials engineers - to compare enamel formulations, coverings and heat-bonding performance.
• Quality and compliance teams - to ensure product performance, reliability and conformity with international practice.

Typical end-markets: industrial and automotive electric machines, power transformers, consumer electronics, aerospace and any application where reliable wire insulation adhesion, flexibility and abrasion resistance matter.

Related standards

• IEC 60851-1 - General notes, definitions and the complete series of test methods for winding wires (normative reference for IEC 60851-3).