IEC 61439 is the international standards series for low-voltage switchgear and controlgear assemblies. Part 1 provides general rules, while the relevant product part supplies the assembly-specific requirements; Part 0 is guidance for specifying an assembly. In a project document, the useful reference identifies the applicable part and edition, rather than using the series number as a standalone product approval.
This is a plain-language guide to reading that reference in a construction procurement package. It explains the public descriptions of three IEC publications and the different document roles they describe. It does not set electrical design values or determine whether an assembly meets a project specification. Those decisions belong with the responsible electrical engineer and the organisations responsible for the equipment.
Which IEC 61439 publication does each number identify?
The official IEC 61439-1:2020 entry describes general definitions, service conditions, construction, technical characteristics and verification. It says that the relevant product part, from Part 2 onwards, applies together with the cited Part 1 requirements when determining assembly conformity. Its public description also says Part 2 applies to assemblies not covered by Part 3 onwards.
| Publication read | Role stated in the public IEC entry | How to read the reference |
|---|---|---|
| IEC 61439-1:2020 | General rules | Read with the applicable product part |
| IEC 61439-2:2020 | Power switchgear and controlgear assemblies | Product-specific requirements for that category |
| IEC TR 61439-0:2022 | Guidance to specifying assemblies | Guidance from the specifier’s perspective |
A project team can use this distinction to make a document reference readable. For example, an equipment schedule can identify the specified publication, while a separate field describes the equipment item. A document title should not be made to carry the whole description of what the project is buying.
What does Part 2 cover?
The IEC 61439-2:2020 public scope addresses power switchgear and controlgear assemblies. The listed scope includes assemblies rated up to 1,000 V AC or 1,500 V DC, indoor and outdoor applications, and stationary or movable assemblies with or without enclosures. It also describes their connection with the generation, distribution, conversion and control of electrical energy.
Those scope boundaries describe a category; they do not select an assembly for a particular building. A buyer should not turn the maximum voltage in a standard’s scope into the project’s required voltage. Preserve the values and equipment description supplied by the electrical engineer. If a schedule names a distribution board, control panel or switchboard without identifying its applicable standard part, return that classification question to the engineer instead of assuming all three names mean the same thing.
Why is Part 0 a technical report?
IEC TR 61439-0:2022 is published as a Technical Report. Its public description explains guidance on assembly characteristics, available options and specification from the specifier’s perspective. It assumes the assembly will be designed, manufactured and verified under the relevant part of the series. It is a guide to expressing the application needs, rather than another product category.
This helps explain the difference between a standard reference and a project brief. Writing a reference tells the reader which publication is intended. Describing the project tells the responsible parties what equipment is needed, where it is located and how it connects with the rest of the design. Neither field should silently substitute for the other. The engineer can use the licensed technical documents to settle the specification; the procurement record can then retain the resulting reference without trying to reproduce the standard.
Keep the edition visible in the equipment schedule
The public IEC entries reviewed for this article are Part 1:2020, Part 2:2020 and Technical Report Part 0:2022. The Part 1 entry says its supplied copy includes corrigenda from December 2021 and September 2023. These are the publications read for this guide, not a declaration of which edition a particular contract or jurisdiction requires.
For document coordination, write the edition beside the reference and retain the engineer’s wording. If one page of a tender names an earlier edition while another names a later edition, make the conflict visible. A quotation should not resolve it by silently deleting the year. Our BOQ guide explains the role of the item schedule; for an electrical package, the engineer’s technical schedule remains the source for electrical requirements.
Do component documents describe the complete assembly?
A component and an assembly are different subjects in a procurement record. The public IEC 62208:2023 description provides a concrete example: it concerns empty enclosures before the assembly manufacturer incorporates switchgear and controlgear components. An empty enclosure therefore has its own document scope. Keep the document title and product reference together so the reader can identify that subject.
Consider a purely illustrative document set: a breaker data sheet, an enclosure drawing and a completed switchboard schedule. These are three different records, even when they belong to the same order. The responsible engineer and assembly manufacturer decide what verification evidence applies. The buyer’s administrative task is to preserve those distinctions when assembling the submittal package, rather than re-label a component document as proof for a complete switchboard.
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What is the difference between design and routine verification?
Schneider Electric’s explanation of IEC 61439 roles, published in 2016, distinguishes the original manufacturer’s design and associated verification from the assembly manufacturer’s responsibility for the completed assembly and routine verification. This is a manufacturer’s explanation of the terminology, not the current licensed standard text. It is useful for understanding why two records can have different subjects even though both use the word verification.
In a project document list, keep each record’s own title. Ask the responsible technical team to identify which assembly or design it addresses. Do not rename an inspection photograph, a functional demonstration or a delivery record as design verification. Equally, do not assume a design-related record identifies the particular completed unit. This is document housekeeping, not an instruction for how to conduct electrical testing or decide whether a verification method is acceptable.
Separate the equipment description from the building interface
An equipment item does not describe every connection around it. For procurement coordination, distinguish the supplied equipment from the site work shown beside it. Ask the engineer to identify the boundaries in the project documents and retain the answer with the drawing revision. If a quotation includes an enclosure, that description alone does not tell the buyer whether adjacent cable installation, supports or site commissioning are included.
Our electrical cable and conduit sourcing overview concerns another part of the electrical package. Cable and conduit requirements should not be replaced by a switchgear assembly reference, or vice versa. The same principle applies to electrical switches and sockets: related products can appear in one construction programme while retaining different product descriptions and technical requirements.
Why are distribution boards described separately in Part 3?
IEC 61439-3:2024 addresses distribution boards intended for operation by ordinary persons, abbreviated DBO. Its public scope describes enclosed, stationary assemblies for indoor or outdoor use and lists specific electrical scope limits. Those limits should be read in the publication, rather than using the word board as the entire classification. The official entry says the 2024 edition replaced the 2012 edition.
The role of the intended operator is part of the terminology. A procurement summary that drops ordinary persons from the title loses information about the product category. That does not mean a buyer should decide the category from who happens to hold a key to a room. The responsible engineer identifies the applicable assembly requirements; the equipment schedule should retain that description instead of shortening every item to panel.
Does a construction project automatically mean Part 4?
IEC 61439-4:2023 concerns assemblies for construction sites, abbreviated ACS. Its public scope describes temporary work locations associated with construction, installation, repair, alteration, demolition or similar operations, and transportable or mobile enclosed assemblies. The words construction site describe the intended assembly application, not every permanent electrical product eventually installed in a completed building.
This distinction is useful in a mixed project package. The temporary works equipment and the permanent installation can appear in the same programme without sharing one equipment classification. Keep their descriptions separate in the BOQ. If an alternative changes the stated product or application, leave that difference visible for the engineer’s review. Our guide to comparing proposed substitutions explains why the alternative should retain its own description rather than inherit an unsupported claim from the original item.
Where this terminology fits in a China procurement discussion
FBM Sourcing manages the entire China procurement package for overseas construction projects. A construction package may contain several electrical product groups, each described by the responsible engineer. This article explains a standard reference that can appear among those documents; it does not state that FBM Sourcing designs, certifies or supplies IEC 61439 assemblies.
For a project enquiry, send the current drawings and BOQ with the relevant engineer-issued specifications. Identify the product groups you want to discuss and any unresolved scope. Our Sourcing Guide explains the procurement process. Send us your drawings and bill of quantities (BOQ). Our team will review it and get back to you.
Sources and reading limits
The publication descriptions above were checked on 22 October 2026. They are publicly readable IEC catalogue descriptions, supplemented by the dated Schneider Electric terminology explanation. The paid IEC standards and Technical Report were not read in full for this article. Clause-level design rules, test procedures and acceptance values are outside its scope; use the applicable licensed documents and responsible electrical professionals for those decisions.
Frequently asked questions
What is the IEC 61439 standard?
It is the standards series for low-voltage switchgear and controlgear assemblies. Its general rules and the applicable product part need to be distinguished in a project reference.
What is the difference between IEC 61439 Part 1 and Part 2?
Part 1 gives general rules. Part 2 addresses power switchgear and controlgear assemblies. The applicable product requirements are read together with the cited general requirements.
Is IEC TR 61439-0 another assembly product standard?
It is a Technical Report offering guidance from the specifier’s perspective. Its role differs from the product requirements in Part 2.
Does a component document establish the status of a complete switchboard?
A document must be matched to its stated subject and scope. The responsible technical team determines whether the evidence addresses the complete assembly; a component file should not be relabelled as an assembly record.
Does this guide confirm an assembly meets the requirements?
No. It explains publication roles and document terminology. Assembly design, verification and project acceptance require the applicable technical documents and responsible professionals.
