IEC 61558-2-23:2010

Overview

IEC 61558-2-23:2010 is an international standard published by the International Electrotechnical Commission (IEC) that specifies particular safety requirements and tests for transformers and power supply units used on construction sites. This standard covers dry-type isolating and safety isolating transformers, including those with electronic circuits, applicable to stationary or portable, single-phase or polyphase transformers with rated voltages up to 1,000 V AC and frequencies up to 500 Hz. It replaces the first edition from 2000 and aligns with the general safety requirements of IEC 61558-1:2005.

Key emphasis areas include electrical safety, thermal performance, and mechanical robustness tailored specifically for the challenging environments of construction sites, ensuring safe and reliable power supply for construction activities.

Key Topics

• Scope and Application
  The standard applies to transformers and power supply units designed for construction site use. It includes transformers with output ratings up to 25 kVA (single-phase) and 40 kVA (polyphase), although higher rated units can be covered based on agreement between manufacturer and purchaser. It excludes transformers intended for distribution networks.

• Safety Requirements
  The standard outlines critical safety criteria covering electrical shock protection, insulation, dielectric strength, creeping distance, protective earth provisions, and protection against dust and moisture ingress.

• Mechanical and Thermal Tests
  Construction site transformers must undergo rigorous mechanical strength and impact tests due to the harsh physical conditions. Thermal testing assures that transformers operate without overheating under normal and fault conditions.

• Testing Protocols
  IEC 61558-2-23 prescribes detailed procedures for routine tests, including no-load voltage measurements, short-circuit and overload protections, and insulation resistance. Specific test conditions cater to construction environments.

• Marking and Information
  Transformers and power supply units must be clearly marked with key operational and safety information, including rated voltage, frequency, power output, and protection class.

• Harmonization with IEC 61558-1
  This part supplements the general safety requirements in IEC 61558-1, adapting them specifically for construction site scenarios. Where there is a conflict between standards, the stricter provisions apply.

Applications

IEC 61558-2-23:2010 serves as a vital reference for:

• Manufacturers designing transformers and power supplies tailored to construction site needs, ensuring compliance with international safety norms.
• Testing and Certification Bodies conducting conformance testing and safety certification for equipment used in construction environments.
• Construction and Electrical Contractors specifying safe, reliable power transformers for use in temporary and permanent installations on building sites.
• Regulatory Authorities adopting this standard to ensure legal compliance and occupational safety in electrical installations on construction sites.

Transformers conforming to this standard provide:

• Enhanced electrical shock protection to workers on site.
• Resistance against dust, moisture, and mechanical damage typical in construction environments.
• Reliable and safe power supply for construction tools and machinery with controlled output voltage ranges.

Related Standards

• IEC 61558-1:2005 – General safety requirements for transformers, reactors, and power supply units.
• IEC 60364-7-704 – Electrical installations of buildings – Safety requirements for construction site electrical supplies.
• IEC 61558-2-16 – Particular requirements for switch mode power supply units (SMPS), relevant when internal frequencies exceed 500 Hz.
• IEC Guide 104 – Guidelines for the preparation and classification of safety publications.

These complementary standards establish a comprehensive safety framework for electrical equipment used in industrial, commercial, and construction settings, facilitating harmonized global compliance.

For professionals involved in electrical equipment manufacturing, testing, or installation on construction sites, IEC 61558-2-23:2010 ensures transformers and power supplies meet stringent safety, performance, and durability standards tailored for demanding construction site conditions. Compliance with this standard enhances workplace safety and equipment reliability, essential for efficient and secure construction operations.