IEC 60939-3:2024

Overview

IEC 60939-3:2024 - Passive filter units for electromagnetic interference suppression (Part 3) specifies safety-focused requirements and test procedures for passive EMI filter units used to attenuate unwanted radio‑frequency signals (noise/interference). The standard applies to single- and multi‑channel filters housed in an enclosure or assembled on a printed circuit board forming a compact entity, where safety tests are appropriate - typically units connected to mains or other supplies up to 1 000 V AC (≤ 400 Hz) or 1 500 V DC. It covers appliance filters but excludes facility filters, cord‑connected filters and direct plug‑in filters.

Key Topics

• Scope and classification
  • Definition of filters covered (mains-connected and other applications where safety tests are required).
  • Classification and usage guidance for class X and Y capacitors in safety contexts.
• Safety and performance tests
  • Separated clauses for safety vs performance test requirements.
  • Detailed test plan, sampling, requalification and structurally‑similar filter rules.
• Electrical and mechanical tests
  • Inductance and capacitance measurement methods (including allowing voltage measurement for inductance).
  • Insulation resistance, voltage proof, impulse voltage, leakage current, insertion loss and discharge/energy considerations.
  • Termination robustness, resistance to soldering heat and temperature‑rise testing.
• Clearances and creepage
  • Updated creepage and clearance tables harmonized with IEC 60938-2 and IEC 60664-1.
• Marking and documentation
  • Marking rules including requirements related to remaining energy after disconnection and detail specification content.
• Component substitution and design
  • Conditions for substituting X and Y capacitors and guidance for multi‑capacitor configurations in three‑phase filters.
• Notable editorial/structural changes
  • Harmonization with ISO/IEC Directives and reorganization of test groups and annex content.

Applications and Who Uses It

IEC 60939-3:2024 is essential for:

• EMI filter manufacturers designing mains-connected passive filters.
• OEMs and system integrators specifying filters for appliances and industrial equipment.
• Compliance and safety engineers performing product certification and type testing.
• Test laboratories and certification bodies applying standardized safety test plans.
• Procurement and quality teams ensuring filter products meet safety and performance expectations.

Practical use cases include appliance input filters, PCB-mounted EMI filters for power electronics, and safety evaluation of multi‑channel filter modules.

Related Standards

• IEC 60384-14 - capacitors for AC mains (note: applies for AC mains ≤100 Hz)
• IEC 60938-2 - related passive filter requirements
• IEC 60664-1 - insulation coordination and creepage/clearance guidance
• ISO/IEC Directives - editorial and structural harmonization

Keywords: IEC 60939-3:2024, passive filter units, EMI suppression, passive EMI filters, safety tests, X capacitors, Y capacitors, creepage and clearance, mains-connected filters.