IEC 61439-1 and IEC 61439-2: Scope, Responsibilities, and Key Requirements

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What Is IEC 61439? Overview and Structure of the Standard Series

The IEC 61439 standard governs the design, construction, and verification of low-voltage switchgear and controlgear assemblies up to 1,000 V AC or 1,500 V DC. Notably, it superseded the older IEC 60439 series, with the transition substantially complete by November 2014.

The series follows a modular structure. Part 1 establishes the common rules that apply universally. In contrast, Parts 2 through 7 are product-specific extensions. Together, IEC 61439-1 and IEC 61439-2 form the most-cited pairing for industrial panel building.

Understanding low-voltage standards is critical for panel builders worldwide. Explore our comprehensive switchgear and busbar standards guide for deeper insights.

The table below summarizes the published parts of the series, each scoped for a specific assembly type:

Importantly, Part 1 cannot be invoked without a product part. Furthermore, where Part 2 conflicts with Part 1, Part 2 takes precedence for power assemblies. Therefore, panel builders must always read both documents in parallel.

Download the complete reference material to support your planning, analysis, or procurement process.

Scope of IEC 61439-1—The General Rules

Part 1 defines the general requirements that apply to every low-voltage assembly up to 1,000 V AC or 1,500 V DC. Specifically, the IEC 61439-1 scope covers terminology, constructional rules, performance criteria, and verification methodology. However, Part 1 does not stand alone. Instead, it is always invoked by one of the product-specific parts.

The standard groups its content into clear engineering domains. Key subjects covered by Part 1 include:

• Definitions and terminology — original manufacturer, assembly manufacturer, functional unit, assembly system.
• Constructional requirements — mechanical strength, clearances, creepage distances, wiring.
• Performance requirements — temperature rise, dielectric withstand, short-circuit withstand, EMC.
• Verification methods — test, calculation, or assessment by comparison with a reference design.
• Marking and documentation — nameplate data, technical file, declaration of conformity.

In practice, understanding Part 1 is a prerequisite to applying any product-specific part. Therefore, engineers who skip the general rules typically fail conformity reviews later. Crucially, Part 1 also defines the split of responsibilities between the original manufacturer and the assembly manufacturer — a topic addressed in a later section.

For technical reference, consult our detailed electrical standards guide covering key compliance requirements.

Scope of IEC 61439-2—Power Switchgear and Controlgear Assemblies

Part 2 covers general-purpose low-voltage power switchgear and controlgear assemblies — abbreviated PSC-assemblies. These are the panels most commonly found in industrial plants, commercial buildings, and machine rooms. Notably, IEC 61439-2 low voltage switchgear scope applies to assemblies with rated voltage up to 1,000 V AC or 1,500 V DC and nominal supply frequency up to 1,000 Hz.

The standard covers fixed, draw-out, indoor, outdoor, stationary, and movable assemblies. Furthermore, it applies whether the assembly is manufactured one-off or in series. Indeed, motor control centers (MCCs) generally fall within its scope when they meet the voltage limits.

However, Part 2 explicitly does not cover certain product types. For example, it excludes distribution boards intended for ordinary persons (handled by Part 3), busbar trunking systems (Part 6), and construction-site assemblies (Part 4). Likewise, individual devices such as circuit breakers and contactors fall under IEC 60947, not IEC 61439-2.

In addition, Part 2 supplements Part 1 rather than replacing it. Specifically, Part 2 adds, modifies, or — where stated — replaces general requirements for PSC-assemblies. As a result, clear scope boundaries prevent the common mistake of applying Part 2 to assemblies that belong to a different product part.

Learn about wiring specifications and component selection in our resource on electrical wires and cables.

The Two-Manufacturer Model—Original Manufacturer vs Assembly Manufacturer

The two-manufacturer model is arguably the most misunderstood concept in IEC 61439-1 and IEC 61439-2. Specifically, the standard splits responsibility between the entity that designs and verifies the assembly system and the entity that builds individual panels. This addresses a key ambiguity in the older IEC 60439 framework.

In practice, the model answers a recurring procurement question: who actually owns conformity? Moreover, it determines who carries the design verification burden and who performs production-line checks. Therefore, every project must identify both parties before any panel is built.

Furthermore, the model interacts directly with the rated diversity factor (RDF), forms of internal separation, and form-of-fault containment declared by the original manufacturer. Indeed, deviation from the verified envelope shifts compliance obligations immediately. The IEC 61439-1 original manufacturer vs assembly manufacturer responsibilities are explored in the two subsections below.

Compliance and safety responsibilities are clarified in our article on ATEX vs IECEx marking standards.

Who Is the Original Manufacturer?

The original manufacturer (OM) is the organization that designed the assembly system and holds the design verification evidence. Typically, this is the switchgear OEM that owns the type-test reports. The OM defines the “verified envelope” — the limits within which a compliant panel can be built. Consequently, the OM bears responsibility for the completeness and correctness of all design verification activities.

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Who Is the Assembly Manufacturer?

The assembly manufacturer (AM), often called the panel builder or system integrator, builds the assembly. Importantly, the AM may or may not be the same legal entity as the OM. The AM must build within the verified envelope, run routine verification on every produced unit, and issue the declaration of conformity. However, if the AM modifies the design beyond that envelope, they assume OM obligations for the changes.

Ensure your panels meet compliance requirements by reviewing our CE marking for control panels article.

The table below summarizes how responsibilities split between the two parties:

Verification Framework — How Compliance Is Demonstrated

IEC 61439 introduced a flexible three-method verification framework. This was a major shift from the binary type-tested versus partially type-tested classification of the older IEC 60439. Indeed, the IEC 61439-2 verification methods test calculation assessment approach treats all three options as equally valid when properly documented.

Verification splits into two distinct activities. First, design verification is performed once for each design. Second, routine verification is performed on every produced assembly. Together, they answer two different questions — “is the design correct?” and “was this unit built correctly?”

Furthermore, the IEC 61439 design verification vs routine verification distinction is essential for procurement. For example, requesting a routine test report from a panel builder is reasonable. In contrast, asking them to repeat a full short-circuit type test for every order is not.

Manufacturing safety protocols are fundamental; explore our guide on busbar manufacturing safety best practices.

In practice, panel builders mix the three methods strategically. Specifically, they may use a tested temperature-rise reference and a calculated short-circuit withstand — combining evidence to cover all required clauses without redundant testing.

The full reference document is available for download to support your research.

Design Verification (Type Verification)

Design verification proves that the assembly design meets every applicable requirement. It can be accomplished through three equivalent methods:

• Testing — physical verification of a prototype (e.g., temperature-rise, short-circuit, dielectric).
• Calculation — engineering analysis based on device power losses or IEC 60865-1 short-circuit rules.
• Comparison with a reference design — demonstrating that the new design falls within a verified one.

Compliance testing and validation are covered extensively in our article on IEC 61439 design verification.

Notably, the standard does not mandate physical testing for every clause. Calculation and comparison are equally valid when traceable evidence is recorded in the technical file.

For readers who want more technical depth, this reference page is a useful starting point.

Routine Verification (Production Testing)

Routine verification runs on every completed assembly before it leaves the factory. Importantly, it confirms manufacturing correctness — not design conformity. The mandatory checks are summarized below:

These records are normally bundled into the Factory Acceptance Test (FAT) documentation.

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Key Technical Requirements Under IEC 61439-1 and IEC 61439-2

Several performance domains drive most engineering decisions when applying IEC 61439-1 and IEC 61439-2. Specifically, temperature rise, short-circuit withstand, and degree of protection cover roughly 80% of verification effort for a typical PSC-assembly. Therefore, knowing how to comply with IEC 61439 for switchgear panels begins with these three.

Each domain has its own clause structure, allowable verification methods, and declared ratings. Moreover, each interacts with the others. For example, a higher IP rating restricts ventilation, which then raises internal temperatures and may force a lower rated diversity factor.

Regional variations exist; compare standards with our article on AS/NZS 61439 versus IEC 61439.

Furthermore, every declared rating must appear on the assembly nameplate and in the technical file. Consequently, undeclared performance is treated as undeclared — and therefore non-compliant — regardless of underlying capability.

The three subsections below summaries the headline requirements engineers reference most often. In addition, they highlight typical verification routes accepted under each clause.

Temperature Rise Limits

Table 6 of IEC 61439-1:2020 sets temperature rise limits referenced against a 35 °C mean ambient. Specifically, bare copper busbars and conductors may rise up to 70 K, while terminals for external insulated conductors are also capped at 70 K. Manual operating parts are limited to 15 K (metal) or 25 K (non-metal) for operator safety. Verification can be achieved by test, calculation, or comparison.

High-voltage testing protocols are essential for verification; explore our overview of IEC 62271-200 type tests.

Short-Circuit Withstand Requirements

The assembly must withstand the prospective short-circuit current at its installation point for a declared duration, typically 1 second. Therefore, the rated short-time withstand current (Icw) and the rated peak withstand current (Ipk) must both be declared. Verification options include physical short-circuit testing or calculation per IEC 60865-1. Importantly, both thermal effects (I²t) and electromagnetic forces on busbars must be considered.
Panel design fundamentals are covered in our comprehensive guide to types of electrical panels.

Degree of Protection (IP Rating)

The complete assembly must achieve the declared IP rating in accordance with IEC 60529. Specifically, IP2X is the minimum for live parts accessible to operators. Furthermore, the rating must be verified for the assembly as a whole — including door seals, cable gland entries, and ventilation openings. In practice, outdoor assemblies typically require IP44 or IP54 minimum to handle dust and water ingress.

Electromagnetic compatibility is critical for modern assemblies; review our detailed industrial control panel EMC guide.

Key Changes from IEC 60439 to IEC 61439

The transition from IEC 60439 to IEC 61439 introduced both structural and technical changes. Specifically, the old TTA/PTTA distinction disappeared. Instead, every assembly is now a “verified assembly,” supported by traceable evidence. Furthermore, the manufacturer concept was formally split into the OM and AM roles.

Environmental factors affect panel performance significantly; learn about pollution degree and overvoltage classifications.

The table below summarizes the most consequential differences:

Notably, existing assemblies certified to IEC 60439 are not automatically withdrawn. However, new designs, new declarations of conformity, and most international tenders now require IEC 61439 compliance.

Conclusion about IEC 60439 to IEC 61439

In summary, IEC 61439-1 provides the foundation — the definitions, performance criteria, and verification framework that govern every low-voltage assembly. Meanwhile, IEC 61439-2 applies those rules specifically to general-purpose power switchgear and controlgear assemblies, modifying or adding requirements where the product demands it.

Furthermore, the two-manufacturer model and the three-method verification framework are the standard’s most practically significant contributions. Together, they shape how IEC 61439-1 and IEC 61439-2 are applied across design offices, panel-building floors, and procurement specifications.

Complete protection strategies integrate multiple standards; discover how to harmonize IP versus NEMA ratings effectively.

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