Manufacturing and assembly of switchgear: how to choose an assembler and verify documentation

Who is considered the manufacturer of the board under the standard

EN IEC 61439-1 does not distinguish between a "builder" and a "design manufacturer"; it defines two specific terms. The design manufacturer (clause 3.10.1) is the organisation that performed the design and verified the low-voltage switchgear and controlgear assembly (switchgear) against the standard. The assembly manufacturer (clause 3.10.2) is the organisation responsible for the manufactured switchgear; according to the note in this clause, this may be the design manufacturer or a third-party organisation.

For procurement, this means the following: switchgear that has been verified by a design manufacturer and assembled by a third-party organisation does not require re-verification of the design, provided that all requirements and instructions from the design manufacturer are fully met (clause 10.1). Verification of the finished assembly is the responsibility of the assembly manufacturer (clause 11.1). If the assembly manufacturer introduces changes that were not included in the design manufacturer's verification, they are considered the design manufacturer regarding those specific changes and are responsible for verifying their compliance (clause 10.1).

EN IEC 61439-1 is the current harmonised standard for switchgear and controlgear assemblies. If documentation refers to older versions of the standard, it is advisable to clarify which edition was used for the design verification.

What must be verified on every product

Section 11 of EN IEC 61439-1 is dedicated to verification. According to clause 11.1, verification must be carried out for every low-voltage switchgear assembly (LV switchgear) to identify material and manufacturing defects and to confirm correct operation; the manufacturer decides whether to perform this during or after the manufacturing process. The verification covers construction (enclosure degree of protection, clearances and creepage distances, protection against electric shock and continuity of protective circuits, installation of components, internal circuits and connections, terminals for external conductors, and mechanical properties) and performance (insulation properties, electrical circuits, and functionality), as well as the requirement in clause 11.1 (c) to confirm that the necessary supply documentation for the LV switchgear has been provided. This clause does not provide for batch sampling.

For low-voltage switchgear assemblies used as main distribution boards, EN IEC 61439-1 applies. According to clause 8.2.1, every enclosure and single-panel assembly, and every panel of a multi-panel assembly within a batch, must undergo verification; the test programme is specified in Table 6, item 21. This includes, for instance, item 15 — insulation resistance measurement, item 18 — verification of the assembly marking, item 19 — verification of the completion of operational documentation (clauses 6.12.1, 6.12.2), and item 20 — verification of completeness. According to clause 8.2.3, the scope of verification may be expanded by agreement between the customer and the manufacturer in the technical specifications, but it may not be reduced.

What must be delivered with the assembly

The LV switchgear itself must feature a rating plate in accordance with clause 6.1 of EN IEC 61439-1: the manufacturer's name or trademark, the type designation or identification number, date of manufacture, rated current, voltage, and frequency, the designation of the IEC 61439-X series standard including the part number, the document number used for manufacturing, and the enclosure serial number.

Documentation is covered in section 6.2 of the same standard. According to clause 6.2.1, the accompanying technical documentation must include parameters from section 5 where necessary; according to clause 6.2.2, it must include loading/unloading, installation, operation, and maintenance conditions, specifically important safety measures, weight, and lifting instructions. A wiring diagram according to clause 6.2.2 is not always mandatory, but is required when the internal electrical schematic of the LV switchgear is not obvious from the physical layout of the equipment, such as in cases involving multiple inlets, generators, or battery banks.

The content of operational documentation is defined by Article 5, Clause 4 of the Technical Regulation (EU) 2016/425 (or equivalent regional low-voltage directives): information regarding the name and manufacturer, intended use, characteristics and parameters, rules for safe operation, installation, storage, transport, sale, and disposal, measures to be taken upon detecting a fault, the name and location of the manufacturer, and the month and year of manufacture. The regulation refers specifically to "operational documentation" rather than an "instruction manual".

The specific title of the document is determined by industry standards. For distribution assemblies, the operational documentation is considered to be the instruction manual, unless technical specifications for specific types of assemblies provide otherwise; the same applies to smaller distribution boards. Mandatory information for distribution assemblies includes, among other things, data confirming conformity, rated currents of the assembly and its components, the IP rating according to EN/IEC 60529, the electrical schematic, installation instructions (including connection in electrical installations with different earthing systems), safety measures, dimensions, and mass. For smaller boards, a similar list applies, which also includes the electrical schematic and installation instructions. According to relevant standards, supplied distribution assemblies must be accompanied by data confirming conformity.

For all types of distribution assemblies, a compartment for storing operational documentation must be provided, and the electrical schematics should be fixed to the inner sides of the doors or in other easily visible locations. Neither EN IEC 61439-1 nor the relevant industry standards for distribution boards require a separate product passport: in the former, the operational document is not specifically named, while in the latter, it is referred to as an instruction manual.

Certificate or Declaration: Both are required

Low-voltage electrical equipment regulations apply to equipment with a rated voltage from 50 to 1000 V (inclusive) for alternating current and from 75 to 1500 V (inclusive) for direct current (Article 1). According to Article 7, Clause 2, equipment listed in the regulation's annex is subject to certification, while all other equipment is subject to a declaration of conformity. Since distribution assemblies are included in the scope of mandatory certification, a certificate is required for a distribution board.

The logic for EMC compliance follows a similar structure: under the relevant technical regulations, specific technical equipment (such as household appliances, personal computers and peripherals, power tools, and musical instruments) requires certification, while other equipment requires a declaration of conformity. Since distribution boards are not listed under the mandatory certification category for electromagnetic compatibility, a declaration of conformity must be issued. Consequently, a distribution board requires two separate documents under two different regulations.

According to the low-voltage equipment regulations, the conformity mark must be applied to every unit in a manner that ensures it remains clearly legible throughout its service life and must be specified in the operating documentation. The specific design of this mark is governed by the applicable regulatory decisions.

How to verify the assembler via documentation

• Ask about the design used for the assembly and who the designer is according to the relevant standards. The specific series or model under which the low-voltage switchgear assembly (LVSA) was manufactured must be stated on the rating plate (in accordance with EN IEC 61439-1); verify that this matches the type of board provided.
• Request the factory acceptance test (FAT) report for the specific serial number. While standards do not strictly mandate that this document be provided to the customer, they do require that testing be performed for every LVSA (per EN IEC 61439-1); therefore, a reputable manufacturer will have a record of it. Note that a "type test report" confirms the design's compliance, whereas an acceptance test report confirms the specific unit's compliance.
• Verify both conformity assessment documents: the certificate for low-voltage equipment and the declaration of conformity for electromagnetic compatibility. Check the validity dates and ensure the manufacturer's name matches the rating plate.
• Check the operating documentation for compliance with the required contents. For main low-voltage distribution boards, the user manual must include specific technical details, including the electrical schematic. For smaller distribution boards, requirements may differ slightly. For other LVSA, a wiring diagram is mandatory if the connections are not obvious from the equipment layout (per EN IEC 61439-1).
• For main distribution boards, check for a dedicated compartment for documentation and ensure the schematic is located on the inside of the door (per EN IEC 61439-1).

How to choose an assembler: what to look for beyond documentation

Documentation demonstrates that the manufacturer is aware of the requirements; production processes demonstrate whether they are actually met. It is useful to clarify whether they have their own manufacturing facility or outsource assembly, which instruments they use to measure insulation resistance and continuity of protective conductors during final acceptance testing, who approves component substitutions if a specific item from the specification is unavailable, and what the lead time is for custom project assemblies. Request the operating manual and the wiring diagram from a recently dispatched assembly—these will reveal whether documentation is completed per unit or merely filled out "in general".

Common mistakes

Assuming a single certificate is sufficient for the board

A certificate for low-voltage equipment safety and a declaration for electromagnetic compatibility (EMC) address different requirements. These are two distinct regulatory frameworks with different forms of conformity for switchgear and controlgear assemblies, meaning two separate documents are required.

Demanding the product manual as a mandatory document

The term "passport" is not mentioned in EN IEC 61439-1 or any other relevant technical standards. Instead, operational documentation is mandatory in accordance with EU safety requirements; for distribution assemblies and switchboards, this must include an instruction manual (as required by EN IEC 61439-2), unless technical specifications state otherwise. If a manufacturer refers to this document as a "passport", the specific title is irrelevant; what matters is that the content and required information are present.

Accepting acceptance testing on a sample basis per batch

According to EN IEC 61439-1, verification testing must be performed for every low-voltage switchgear assembly (LV switchgear). For distribution boards and panelboards, testing is required for every enclosure and every single panel within a multi-panel assembly. Sampling a batch does not exempt the manufacturer from testing each individual unit.

Assuming any electrician can assemble a board

The entity assembling the board becomes the manufacturer of the LV switchgear under EN IEC 61439-1 and is responsible for the product and its acceptance tests. If the assembler deviates from the verified design, they also assume the role of the designer regarding those changes and must confirm that the modifications comply with the standard.

Replacing components in a finished board with equivalents

Replacing components in a way not specified by the original designer constitutes a change to the verified design. According to EN IEC 61439-1, such changes require type testing (as per Section 10) to assess the impact of the modifications on the assembly's performance; if a negative effect is found, additional verification is required. While the standard does not demand a complete repetition of all design tests, the responsibility for the modified part shifts to the party that introduced the change. An exception applies to components that comply with their own specific standards (per Section 8.5.3) and are installed strictly according to the manufacturer's instructions: these do not require re-testing.

Conclusion

Before paying for a switchboard, ensure the following four items are verified: a rating plate in accordance with Section 6.1 (showing the series number and serial number), a valid Declaration of Conformity, an instruction manual including a wiring diagram (mandatory for distribution boards and switchboards), and confirmation of acceptance testing for that specific serial number. If the assembler cannot provide any of these, the board is not ready for acceptance. If you require a custom-designed board or a construction site distribution board from stock, please submit an inquiry via our contacts page; we will coordinate the configuration based on your specific site requirements.