IEC 61558-2-1:2021

Overview

IEC 61558-2-1:2021 is an international standard published by the International Electrotechnical Commission (IEC) that specifies safety requirements and testing procedures for separating transformers and power supply units incorporating separating transformers for general applications. This document is integral to ensuring electrical, thermal, and mechanical safety aspects in such devices, including those incorporating electronic circuits. The standard applies to stationary or portable, single-phase or polyphase, air-cooled (either natural or forced), independent or associated dry-type transformers, with windings that can be either encapsulated or non-encapsulated.

This third edition of IEC 61558-2-1 updates its structure and references to align with IEC 61558-1:2017 and introduces a new symbol for power supply units with linearly regulated output voltage. It is recognized as a group safety publication under IEC Guide 104, making it a critical resource for manufacturers, compliance engineers, and technical committees developing products or further related standards.

Key Topics

• Scope: Covers the safety of separating transformers and power supply units with rated supply voltages not exceeding 1,000 V AC or 1,415 V ripple-free DC, and output voltages not less than 50 V AC or 120 V ripple-free DC for independent transformers.
• General Requirements: Applies to single-phase transformers up to 1 kVA and polyphase transformers up to 5 kVA. Higher outputs may be agreed upon by manufacturer and purchaser.
• Test Procedures: Includes detailed guidance for assessment of electrical insulation, protection against electric shock, short-circuit performance, mechanical integrity, heating, and marking requirements.
• Marking and Symbols: Requires relevant symbols to indicate the type of transformer, including a new symbol for linearly regulated power supply units.
• Output Voltage Criteria: Specifies strict limits on no-load and on-load output voltage, ensuring user safety by minimizing the risk of electrical hazards.
• Environmental and Operational Considerations: Addresses protection against dust, moisture, and other harmful influences, as well as testing for resistance to heat, fire, tracking, and rust.

Applications

IEC 61558-2-1:2021 serves as a fundamental safety benchmark in several industries and applications, including:

• General Electrical Installations: Ensures safety in transformers and power supply units used for voltage adaptation in various equipment.
• Industrial Automation: Provides guidance for safe construction and operation of transformers integrated into machinery and process control systems.
• Building Services: Supports compliance in transformers used for lighting systems, control panels, and HVAC equipment.
• Testing and Certification: Used by testing bodies and certification organizations to evaluate if products conform to international safety requirements.
• Product Design: Assists manufacturers in designing and labeling transformers and power supplies to meet globally recognized safety criteria, facilitating market access and regulatory approval.

Compliance with IEC 61558-2-1 helps manufacturers reduce product liability risk, promote user safety, and streamline access to international markets.

Related Standards

• IEC 61558-1:2017 - Safety of transformers, reactors, power supply units and combinations thereof - Part 1: General requirements and tests.
• IEC 61558-2-16 - Particular requirements for switch mode power supply units.
• IEC 60076-11: Power transformers - Part 11: Dry-type transformers (not directly covered by IEC 61558-2-1).
• IEC 60204-1: Safety of machinery - Electrical equipment of machines.
• IEC GUIDE 104: Preparation of safety publications and the use of basic and group safety publications.
• ISO/IEC GUIDE 51: Safety aspects - Guidelines for their inclusion in standards.

By aligning with IEC 61558-2-1:2021 and the above related standards, organizations can ensure their products adhere to best practices in transformer and power supply safety, maintain regulatory compliance, and meet the expectations of end-users worldwide.