EN 61558-2-6:2009 PDF

Overview

EN 61558-2-6:2009 (IEC 61558-2-6:2009) is the European adoption of the international standard that sets particular safety requirements and tests for safety isolating transformers and power supply units incorporating safety isolating transformers for supply voltages up to 1 100 V. This second edition replaces the 1997 edition, updates alignment with EN/IEC 61558-1 (2005) and expands voltage ranges in line with relevant technical committees. The part is a group safety publication (IEC Guide 104) and is intended to be used together with the latest edition of IEC/EN 61558-1.

Key topics and technical requirements

This standard supplements and modifies the general rules in Part 1 by addressing particular aspects for isolating transformers and associated power supplies. Major technical topics include:

• Ratings and classification - defined supply and output ratings and product classes for safety isolating transformers.
• Marking and documentation - required markings, information and instructions for safe installation and operation.
• Protection against electric shock - insulation, earthing and construction measures to limit user exposure to live parts.
• Output performance - tests and requirements for output voltage under load, no-load voltage and allowable output differences.
• Short-circuit and overload behaviour - test methods for short-circuit voltage, overload protection and performance under fault conditions.
• Thermal performance and heating - temperature rise limits, heating tests and thermal protection.
• Mechanical strength and ingress protection - mechanical tests, enclosure and protection against dust/moisture.
• Insulation and dielectric tests - insulation resistance, dielectric strength, leakage current and creepage/clearance distances (including annexes for material groups).
• Construction and components - requirements on internal wiring, terminals, screws, components and resistance to heat, fire and tracking.
• Annexes and test details - supplementary tables and guidance (e.g., creepage/clearance distances, application of IEC 60664-1 rules).

Practical applications and users

EN 61558-2-6 is essential for:

• Transformer and power supply manufacturers designing safety isolating transformers or PSUs that incorporate them.
• Product safety engineers ensuring designs meet European and international safety test regimes.
• Test laboratories and certification bodies performing type testing, conformity assessment and issuing safety approvals.
• Procurement and compliance teams specifying safety requirements for electrical equipment that uses isolating transformers.

Typical applications include general-purpose isolating transformers and switch‑mode or linear power supply units that incorporate an isolating transformer where safety, insulation and fault behavior must be demonstrated.

Related standards

• EN/IEC 61558-1:2005 - General requirements and tests (to be used in conjunction with EN 61558-2-6).
• IEC 60664-1 - Insulation coordination (referenced for creepage and clearance rules).

Keywords: EN 61558-2-6:2009, IEC 61558-2-6, safety isolating transformers, power supply units, transformer safety, creepage distances, dielectric strength, insulation, testing, certification.