IEC 61439-1:2020

Overview

IEC 61439-1:2020 - "Low‑voltage switchgear and controlgear assemblies – Part 1: General rules" - defines the general rules, terminology, service conditions, construction and technical characteristics, and verification requirements for low‑voltage switchgear and controlgear assemblies. It is the foundational document of the IEC 61439 series and is used together with the relevant product‑specific parts (Part 2 onward) to determine assembly conformity. This third edition (2020) replaces the 2011 edition and includes important technical updates and corrigenda.

Key topics and requirements

• Scope and definitions: common terms, constructional units, insulation classes and service conditions that apply across the IEC 61439 series.
• Service conditions: normal and special environmental conditions, ambient temperature, humidity, pollution degree and transport/storage conditions.
• Construction requirements: materials, mechanical strength, corrosion resistance, lifting provisions and use of insulating materials.
• Degree of protection: requirements referenced to IP (ingress protection) and IK (mechanical impact) codes for enclosures.
• Clearances and creepage: electrical separation to manage insulation and prevent breakdown.
• Protection against electric shock: requirements for basic and fault protection, including the new concept of class I and class II assemblies.
• Incorporation of devices and components: rules for fixed and removable parts, accessibility, barriers and marking.
• Internal circuits and terminals: main and auxiliary circuit rules, conductor identification and terminal requirements.
• Performance requirements: dielectric properties (power‑frequency and impulse withstand), temperature‑rise limits and the new group rated current concept (temperature‑rise verification focused on group rated current).
• Short‑circuit: coordination, rated short‑time and peak withstands, and conditional short‑circuit current information.
• EMC: electromagnetic compatibility considerations for assemblies.
• Design verification: tests and verifications required to demonstrate conformity to the standard.

Notable technical changes in the 2020 edition:

• Clarification on testing of power electronic equipment (e.g., converters, UPS) to their product standards while their incorporation into assemblies follows IEC 61439 rules.
• Introduction of group rated current and refocus of temperature‑rise verification on that characteristic.
• Addition of explicit DC requirements.
• Introduction of class I / class II assembly classification for shock protection.

Applications

IEC 61439-1:2020 is applied when designing, manufacturing, specifying, testing or installing low‑voltage switchgear and controlgear assemblies used in:

• industrial and manufacturing plants
• commercial buildings and infrastructure
• utility distribution and substations
• data centers, renewable energy systems and EV charging installations
• OEM panel builders and switchboard manufacturers

Who should use this standard

• Electrical designers and panel builders
• Product manufacturers and integrators
• Test laboratories and conformity assessment bodies
• Specifiers, consulting engineers and asset owners
• Regulatory and certification authorities

Related standards

• IEC 61439‑2 and subsequent parts (Part 2 onward) - product‑specific requirements and verification methods that apply together with Part 1 for assembly conformity.
• Product standards for power converters, UPS and drive systems (these products are tested to their own standards but incorporated per IEC 61439 series).

Keywords: IEC 61439-1, low-voltage switchgear, controlgear assemblies, group rated current, temperature-rise verification, class I class II, DC requirements, design verification, IP code, IK code, short-circuit withstand, EMC.