IEC 61439-4:2023

Overview

IEC 61439-4:2023 - "Low‑voltage switchgear and controlgear assemblies - Part 4: Particular requirements for assemblies for construction sites (ACS)" specifies the particular requirements and verification criteria for low‑voltage electrical assemblies intended for temporary construction‑site use. The standard applies to transportable (semi‑fixed) and mobile assemblies with enclosures where the rated voltage does not exceed 1 000 V AC or 1 500 V DC, including assemblies that incorporate transformers with primary/secondary voltages within those limits. Edition 2.0 (2023) is a technical revision aligned with IEC 61439‑1:2020 structure and content.

Key Topics

IEC 61439‑4:2023 addresses the following technical areas relevant to safe, robust construction‑site electrical assemblies:

• Rated voltage and current characteristics - declaration of rated operational, insulation and impulse voltages for ACS.
• Scope of use - definition of construction‑site environments (temporary workplaces, indoor/outdoor).
• Mechanical and material requirements - strength, corrosion resistance, UV resistance, lifting provisions and mechanical operation.
• Enclosure protection - degree of protection (IP code) and mechanical impact resistance (IK code) for outdoor/rough use.
• Clearances and creepage distances - insulation coordination appropriate for low‑voltage ACS.
• Protection against electric shock - basic and fault protection, protective conductor integrity, class II considerations.
• Thermal performance - temperature‑rise limits and ambient‑temperature adjustments for rated currents.
• Short‑circuit performance - short‑circuit withstand strength, peak and short‑time currents, and coordination of protective devices.
• Internal wiring and terminals - main/auxiliary circuits, conductor identification, cable outlets and terminal ratings.
• Electromagnetic compatibility (EMC) and surge protection considerations.
• Design verification and testing - verification methods referenced to IEC 61439‑1:2020, including dielectric and mechanical tests.
• Documentation and marking - designation, instructions for handling/installation/maintenance, and device identification.

Applications and Who Uses It

IEC 61439‑4:2023 is intended for professionals involved with electrical distribution on construction sites:

• Manufacturers of portable and mobile low‑voltage switchgear assemblies (ACS).
• Design engineers and specifiers preparing site power distribution systems.
• Contractors and site electricians selecting compliant assemblies for temporary installations.
• Testing laboratories and certification bodies verifying performance and safety.
• Safety managers and procurement teams ensuring installations meet regulatory and occupational safety requirements.

Using IEC 61439‑4 helps ensure reliable performance under harsh, temporary site conditions, minimizes electrical hazards, and supports compliance during inspection and certification.

Related Standards

• IEC 61439‑1:2020 - General rules for low‑voltage switchgear and controlgear assemblies (referenced and aligned in this edition).
• Other parts of the IEC 61439 series for broader switchgear family requirements and verifications.