IEC 61558-1-2017 PDF

Full title and description

Safety of transformers, reactors, power supply units and combinations thereof — Part 1: General requirements and tests. This document establishes safety requirements and test procedures for dry‑type transformers, power‑supply units (including switch‑mode power supplies), reactors and combinations thereof that are not part of distribution networks, covering electrical, thermal and mechanical safety aspects.

Abstract

IEC 61558-1:2017 (third edition, redline version available) is a technical revision of the Part 1 group safety publication for transformers, reactors and power‑supply units. It consolidates previous corrigenda and amendments, introduces updated requirements and test methods (for example for fully insulated winding wires, overvoltage categories, simulated load and short‑circuit tests aligned with IEC 60076‑11, new symbols and marking requirements) and clarifies mechanical and environmental testing. The redline version shows all changes compared to the previous edition.

General information

• Status: Published / Current (group safety publication).
• Publication date: 29 September 2017 (third edition, RLV).
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 29.180 (Transformers. Reactors); related classifications include connector device codes where applicable.
• Edition / version: Edition 3.0 (2017), redline version available (IEC 61558-1:2017 RLV).
• Number of pages: 556 pages for the RLV electronic publication (official IEC webstore record).

Scope

Part 1 lays down general safety requirements and test methods for stationary or portable, single‑phase or polyphase dry‑type transformers, reactors and power‑supply units (including switch‑mode types) whose windings may be encapsulated or non‑encapsulated and which do not form part of distribution networks. It addresses ratings, insulation, clearance and creepage, temperature limits and measurement, short‑circuit and overload considerations, mechanical strength, enclosure protection (IP codes) and marking. Specific product types and additional requirements are handled in the relevant Part 2 sub‑parts.

Key topics and requirements

• General electrical safety: insulation systems, clearances and creepage distances and requirements by overvoltage category.
• Temperature limits, measurement methods and simulated‑load testing (including alternative methods aligned with IEC 60076‑11).
• Requirements and tests for fully insulated winding wires (FIW) and related aging and partial‑discharge provisions.
• Short‑circuit and overload protection and test methods (including back‑to‑back and simulated‑load approaches).
• Mechanical and environmental tests: vibration (including vehicle/railway applications), tumbling/barrel tests for plug‑in units, and repetition tests for dielectric strength.
• Updated marking and symbol requirements (overvoltage categories, altitude, minimum temperature, plug‑in damage symbol, etc.).
• Clarifications for toroidal core constructions, connector dimensioning and revised enclosure protection (IP) considerations.
• Interaction with related standards (references to IEC 60076‑11 for certain test methods).

Typical use and users

IEC 61558‑1:2017 is used by transformer and power‑supply designers, manufacturers, test laboratories, conformity assessment bodies, standards committees and safety engineers to design, test and certify products against internationally accepted safety criteria. Regulatory bodies and national standards organizations use it as the basis for national/adopted versions and for aligning product safety requirements.

Related standards

Relevant related documents include the Part 2 series of IEC 61558 (product‑type specific requirements), IEC 60076‑11 (tests and requirements referenced for some temperature and short‑circuit methods), and regional/adopted versions such as EN IEC 61558‑1 (European adoption). Users should consult the Part 2 sub‑parts that apply to a specific transformer or power‑supply type.

Keywords

transformer safety, power supply safety, reactor safety, clearance and creepage, overvoltage categories, fully insulated winding wire, short‑circuit test, overload protection, IEC 61558, group safety publication, test methods.

FAQ

Q: What is this standard?

A: IEC 61558‑1:2017 is the third‑edition international standard that specifies general safety requirements and test methods for dry‑type transformers, reactors and power‑supply units and combinations thereof.

Q: What does it cover?

A: It covers electrical, thermal and mechanical safety requirements — including insulation, clearances/creepage, temperature testing, short‑circuit and overload tests, mechanical robustness, marking and symbols — and establishes general tests that apply unless a Part 2 sub‑part provides specific requirements.

Q: Who typically uses it?

A: Product designers, manufacturers, test houses, certification bodies, standards committees and regulatory authorities in the electrotechnical sector. It is also used by compliance engineers preparing technical documentation for market access.

Q: Is it current or superseded?

A: The 2017 third edition is the current edition. It cancelled and replaced the second edition (2005) and its amendments/corrigenda. A Corrigendum 1 for the 2017 edition was published in December 2025; users should apply the 2017 edition together with any published corrigenda.

Q: Is it part of a series?

A: Yes — IEC 61558 is a multi‑part series. Part 1 contains general requirements and tests; the Part 2 sub‑parts contain product‑specific requirements for particular transformer and power‑supply types.

Q: What are the key keywords?

A: Transformer, reactor, power supply, safety, test methods, insulation, clearance, creepage, overvoltage category, FIW, short‑circuit, overload, IEC 61558‑1.