IEC 61558-2-9:2024

Overview

IEC 61558-2-9:2024 is the third edition of the IEC safety standard for transformers and power supply units for class III handlamps. It specifies particular requirements and tests for transformers (including those with electronic circuits) and power supplies that provide safety extra-low voltage (SELV) for handlamps. This edition updates the 2010 version, adjusts structure and references to align with IEC 61558-1:2017, adds a symbol for linearly regulated outputs, and expands applicability beyond tungsten filament lamps. IEC 61558-2-9:2024 has the status of a group safety publication (IEC Guide 104).

Key topics and technical requirements

The standard supplements IEC 61558-1 and focuses on practical safety and test criteria for class III handlamp transformers and linear power supplies. Major technical topics include:

• Scope and ratings: single-phase, air-cooled dry-type transformers (stationary or portable); rated supply voltage ≤ 1 000 V AC; rated output ≤ 10 kVA; internal operational frequencies ≤ 500 Hz (SMPS handled jointly with IEC 61558‑2‑16).
• Output limits for class III: no-load and rated outputs not exceeding 50 V AC or 120 V ripple‑free DC, with only small no-load/rated voltage differences.
• Protection against electric shock: SELV considerations and required insulation measures.
• Electrical tests: insulation resistance, dielectric strength, leakage current, short‑circuit and overload behavior.
• Thermal and mechanical requirements: heating limits, mechanical strength, resistance to heat/fire/tracking and corrosion.
• Marking, classification and symbols: including new symbol for linearly regulated output voltage.
• Construction and components: internal wiring, terminals, earthing provisions, creepage/clearance distances.
• Test methods and documentation: general notes on tests and required records to demonstrate compliance.

Practical applications

IEC 61558-2-9 is intended for use where safe low-voltage handlamps are required - for example, workshop and inspection handlamps that rely on SELV transformers or linear power supplies. The standard ensures that transformers and linear power supply units used with class III handlamps meet electrical, thermal and mechanical safety expectations.

Who should use this standard

• Transformer and power supply manufacturers (design and compliance)
• Product safety and compliance engineers
• Test laboratories and certification bodies
• OEMs integrating handlamp transformers into lighting products
• Regulatory and standards committees

Related standards

• IEC 61558-1:2017 (general requirements for safety of transformers and power supplies)
• IEC 61558-2-16 (particular requirements for switch mode power supplies - used together when applicable)
• IEC Guide 104 (group safety publication guidance)

Keywords: IEC 61558-2-9, transformer safety, class III handlamps, power supply units, SELV, handlamp transformers, IEC 2024.