![\"MNS](\"https:\/\/lanshanelectric.com\/wp-content\/uploads\/2026\/08\/MNS-Low-Voltage-Withdrawable-Switchgear-1.jpg\")
<\/figure>\n\n\n\nIEC 61439 is the international series for low-voltage switchgear and controlgear assemblies. The current IEC 61439-1:2020<\/a> contains the general definitions, service conditions, construction requirements, technical characteristics and verification requirements used by the relevant product parts. IEC states explicitly that Part 1 is applied together with the relevant part from Part 2 onward.<\/p>\n\n\n\n For power switchgear and controlgear assemblies used in industrial and commercial distribution, IEC 61439-2:2020<\/a> provides the specific requirements. Its scope includes assemblies up to 1,000 V AC or 1,500 V DC and covers indoor and outdoor power distribution and control applications.<\/p>\n\n\n\n That distinction is important. A proposal that cites only IEC 61439-1 has identified the general rules, but it has not yet stated the complete product-part basis for a power switchgear assembly. Buyers should ask which part applies to the equipment being supplied and which edition is being used.<\/p>\n\n\n\n For the type of low voltage distribution equipment discussed on Lanshan\u2019s switchgear tegangan rendah<\/a> pages, IEC 61439-2 is normally the product part that needs to be considered together with IEC 61439-1. The manufacturer should identify that basis in the technical submission rather than leaving the buyer to infer it from a catalogue statement.<\/p>\n\n\n\n IEC 61439-1 also introduced the concept of group rated current for circuits within a loaded assembly and places strong emphasis on temperature-rise verification. For buyers, the practical consequence is that the current rating of one device does not automatically establish the continuous loading capability of the complete assembly.<\/p>\n\n\n\n When reviewing IEC 61439 switchgear, keep three levels separate: the rating of a component, the rating of an individual circuit within the assembly, and the declared characteristics of the complete assembly. They are related, but they are not interchangeable.<\/p>\n\n\n\n One of the most important IEC 61439 concepts is the distinction between design verification and routine verification. Design verification demonstrates that the assembly design satisfies the applicable requirements. Routine verification checks each manufactured assembly for the specified production-related items before delivery.<\/p>\n\n\n\n Design verification can involve different permitted methods depending on the characteristic being assessed. The IEC 61439 framework does not mean that every characteristic must always be proven by a new physical test on every project. Equally, it does not allow a manufacturer to replace required evidence with an unsupported statement that the design is \u201csimilar.\u201d<\/p>\n\n\n\n For a buyer, the useful document is a verification schedule. It should identify the characteristic being verified, the method used, the reference design or test evidence where applicable, and the conditions under which that evidence remains valid for the offered assembly.<\/p>\n\n\n\n Routine verification is performed on the manufactured assembly. It does not repeat the entire design-verification program. Instead, it confirms defined aspects of workmanship, construction and function for the actual unit produced.<\/p>\n\n\n\n Ask for routine records that can be traced to the delivered panel or lineup. Serial numbers, drawing revisions and equipment identifiers should connect the verification record to the switchgear that arrives on site. A generic factory checklist with no traceability is much less useful for project handover.<\/p>\n\n\n\n A frequent IEC 61439 procurement mistake is to collect certificates for circuit breakers, contactors, meters and enclosures and treat the folder as proof that the completed panel complies. Those documents are useful, but they do not establish the characteristics created by assembling the components together.<\/p>\n\n\n\n The complete assembly introduces busbars, internal conductors, spacing, ventilation, cable terminations, protective-device coordination, internal separation and simultaneous loading. Those factors can change thermal and short-circuit behavior even when every individual component is correctly certified to its own product standard.<\/p>\n\n\n\n For example, Lanshan\u2019s GGD switchgear tegangan rendah<\/a> is a fixed assembly, while the MNS withdrawable switchgear<\/a> uses a different functional-unit structure. Both need project-specific assembly verification; a breaker certificate alone cannot describe either complete layout.<\/p>\n\n\n\n The most visible number in a switchgear quotation is often the main bus current, but IEC 61439 requires a more disciplined look at loading. Ask which current is being declared for the assembly, for the incoming circuit and for the outgoing circuit groups, and under what ambient and installation conditions those values apply.<\/p>\n\n\n\n A 1,600 A incoming breaker does not automatically make the entire assembly a 1,600 A continuously loaded system. Busbar size, internal conductor arrangement, enclosure ventilation, neighboring circuits and ambient conditions all influence temperature rise.<\/p>\n\n\n\n Submit the actual feeder schedule and simultaneous operating conditions. If six feeders are installed but only four normally operate together, state that operating basis. If future expansion could make all six heavily loaded at the same time, show that scenario separately.<\/p>\n\n\n\n For the proposed assembly, the manufacturer should be able to explain which loading assumptions support the proposed arrangement. If the project later changes from intermittent loads to continuous process loads, the thermal review may need to be revisited rather than assuming the original panel remains unchanged in capability.<\/p>\n\n\n\n A quotation that says \u201c50 kA\u201d without identifying the characteristic is incomplete. IEC 61439 uses different short-circuit concepts, and the buyer needs to know which one is being declared and the conditions behind it.<\/p>\n\n\n\n The distinction matters because the complete assembly and the breaker perform different functions during a fault. A breaker may have a high interrupting capability while the surrounding busbar or conductor arrangement has a different verified withstand characteristic.<\/p>\n\n\n\n Send the project fault-level data and identify every permitted source configuration. A bus coupler that is normally open can change the available fault current when closed. The IEC 61439 review should therefore be tied to the actual single-line diagram, not a generic panel catalogue.<\/p>\n\n\n\n Temperature rise is one of the most practical IEC 61439 topics because it connects the electrical design to the physical assembly. The 2020 edition of IEC 61439-1 refocused temperature-rise verification around the group rated current concept, while IEC 61439-2 includes specific provisions for power assemblies and for natural or active cooling within defined conditions.<\/p>\n\n\n\n For the buyer, this means that enclosure size, ventilation openings, internal conductor placement and circuit grouping should be reviewed together. Adding filters, changing the IP arrangement or replacing a breaker with a different loss profile can affect the thermal condition even if the headline current rating remains unchanged.<\/p>\n\n\n\n Request the ambient-temperature assumptions used for the verification and compare them with the switchroom or outdoor site. If the project has unusually high ambient temperature, altitude or restricted airflow, the manufacturer should confirm the applicable rating for those conditions instead of relying on a standard laboratory assumption.<\/p>\n\n\n\n IEC 61439-2 addresses forms of internal separation within power switchgear and controlgear assemblies. The form should be selected from the project\u2019s operating and maintenance requirements, not treated as a prestige ranking where the highest number is automatically best.<\/p>\n\n\n\n Ask what needs to be separated: busbars from functional units, one functional unit from another, or terminals for external conductors. Then ask what must be isolated before each maintenance task. The declared form should be shown on the assembly drawing so the buyer can see how the physical construction implements the requirement.<\/p>\n\n\n\n Internal separation does not automatically establish internal arc performance, nor does it create permission for energized maintenance. If the project requires internal arc-fault protection, define that as a separate requirement and request the relevant evidence under the applicable technical specification and project rules.<\/p>\n\n\n\n The IP rating of an empty enclosure is not automatically the IP rating of the completed IEC 61439 switchgear. Cable entries, ventilation openings, doors, meters and operator interfaces all become part of the final enclosure configuration.<\/p>\n\n\n\n When the project requires a particular IP level, request confirmation for the complete as-supplied assembly. Then identify which site-installed items could alter that protection. A gland plate drilled after delivery or a field-installed display can change the enclosure conditions if it is not incorporated using an approved arrangement.<\/p>\n\n\n\n Keep ingress protection separate from corrosion resistance, UV resistance and condensation control. These environmental characteristics may need additional requirements beyond the IP designation.<\/p>\n\n\n\n IEC 61439 distinguishes responsibilities around the assembly design and final manufacture. For procurement, the important question is simple: which organization takes responsibility for the completed assembly supplied under the purchase order?<\/p>\n\n\n\n If a panel builder uses a verified reference design, request the instructions and evidence that support the final configuration. If substitutions or modifications are introduced, ask how their effect on the relevant verified characteristics has been assessed.<\/p>\n\n\n\n This responsibility becomes particularly important in customized low voltage panels. \u201cCustom-built\u201d should not mean \u201coutside the verification process.\u201d The approved drawing, component list and verification basis should describe the same equipment.<\/p>\n\n\n\n Rather than asking one yes-or-no question \u2014 \u201cIs it IEC 61439 compliant?\u201d \u2014 build an evidence matrix. This makes missing information visible and prevents a collection of unrelated certificates from being mistaken for a complete technical submission.<\/p>\n\n\n\n Keep every unresolved row open until the project reviewer accepts the evidence. A \u201ccertificate received\u201d status is not the same as \u201crequirement verified.\u201d<\/p>\n\n\n\n Consider a hypothetical IEC 61439 switchgear project designed around an 800 A incoming circuit. Late in the project, the owner increases the expected load and asks for a 1,000 A breaker while keeping the original enclosure and internal conductor arrangement.<\/p>\n\n\n\n The device itself may be available in a 1,000 A rating, but that does not prove the assembly can continuously carry the revised duty. The change can affect conductor loading, heat dissipation, terminal sizes and protection settings. The manufacturer should therefore review the temperature-rise and other affected verification conditions before approving the substitution.<\/p>\n\n\n\n The same principle applies in the opposite direction. Replacing a breaker with a smaller frame does not automatically prove that every other assembly characteristic remains unchanged. IEC 61439 compliance is configuration-based, not a label that permanently attaches to the cabinet shell.<\/p>\n\n\n\n Before releasing the low voltage assembly for manufacture, close the main technical inputs. Issue the approved single-line diagram, feeder schedule, fault-level data, service conditions, required form of separation, IP requirement and cable-entry information.<\/p>\n\n\n\n Request a rated-data schedule, general arrangement, verification matrix and list of technical deviations. Define which documents require approval and which are provided for information. This keeps the project team from discovering after manufacture that the panel was designed around different loading or installation assumptions.<\/p>\n\n\n\n During handover, collect the final drawings and unit-specific routine verification records. If the project includes monitoring or communication functions, keep those interface tests separate from the assembly electrical verification. A successful Modbus communication test does not prove temperature-rise or short-circuit capability.<\/p>\n\n\n\n Lanshan supplies fixed GGD and withdrawable MNS low voltage switchgear configurations for industrial and commercial distribution projects. Review these products through the same IEC 61439 process: define the operating duty first, then confirm the project-specific ratings, construction and verification evidence.<\/p>\n\n\n\nIEC 61439-1 and IEC 61439-2 Are Used Together<\/h2>\n\n\n\n
Design Verification and Routine Verification Are Different<\/h2>\n\n\n\n
Verifikasi Desain<\/h3>\n\n\n\n
Routine Verification<\/h3>\n\n\n\n
Component Certificates Do Not Prove Assembly Compliance<\/h2>\n\n\n\n
Verify Current Ratings Under Real Loading Conditions<\/h2>\n\n\n\n
![\"Low](\"https:\/\/lanshanelectric.com\/wp-content\/uploads\/2026\/08\/Construction-site10.jpg\")
<\/figure>\n\n\n\nUse the Load Schedule, Not Only Breaker Frame Sizes<\/h3>\n\n\n\n
Short-Circuit Ratings Need More Than One kA Number<\/h2>\n\n\n\n
Characteristic<\/th> What it tells the buyer<\/th> What to request<\/th><\/tr><\/thead> Waktu singkat tahan arus, Icw<\/td> The RMS short-circuit current the assembly can withstand for a stated duration<\/td> Current value, duration and configuration covered<\/td><\/tr> Puncak menahan arus, Ipk<\/td> The peak current the assembly can withstand<\/td> Declared peak value and verification basis<\/td><\/tr> Arus hubung singkat bersyarat, Icc<\/td> Capability when protected by a specified upstream short-circuit protective device<\/td> Exact protective device and conditions<\/td><\/tr> Breaker Icu \/ Ics<\/td> Breaking capacities of the circuit breaker itself<\/td> Device rating at the operating voltage; do not substitute for assembly rating<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Temperature-Rise Verification Is a System Issue<\/h2>\n\n\n\n
Forms of Internal Separation Must Match the Maintenance Need<\/h2>\n\n\n\n
![\"Low](\"https:\/\/lanshanelectric.com\/wp-content\/uploads\/2026\/07\/Low-voltage-switchgear.jpg\")
<\/figure>\n\n\n\nIngress Protection Is for the Completed Configuration<\/h2>\n\n\n\n
Ask Who Is the Assembly Manufacturer<\/h2>\n\n\n\n
Use a Verification Matrix During Technical Bid Review<\/h2>\n\n\n\n
Persyaratan proyek<\/th> Masukan pembeli<\/th> Supplier evidence or confirmation<\/th><\/tr><\/thead> Applicable standard<\/td> Required IEC 61439 parts and editions<\/td> Declared conformity basis and scope<\/td><\/tr> Current capability<\/td> Load schedule and simultaneous demand<\/td> Assembly and circuit rated-current data plus temperature-rise basis<\/td><\/tr> Fault duty<\/td> Prospective fault current and duration<\/td> Icw \/ Ipk \/ Icc as applicable and verification evidence<\/td><\/tr> Internal separation<\/td> Maintenance and access requirement<\/td> Declared form shown on drawings<\/td><\/tr> Ingress protection<\/td> Site exposure and required IP<\/td> Completed-assembly IP configuration<\/td><\/tr> Routine verification<\/td> Required handover records<\/td> Unit-specific routine verification linked to serial numbers<\/td><\/tr> Changes after approval<\/td> Updated drawings or substitutions<\/td> Assessment showing which verifications remain applicable<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Example: Why a Breaker Upgrade Can Trigger a New Review<\/h2>\n\n\n\n
![\"Low](\"https:\/\/lanshanelectric.com\/wp-content\/uploads\/2026\/08\/Construction-site06.jpg\")
<\/figure>\n\n\n\nWhat Buyers Should Request Before Production Release<\/h2>\n\n\n\n
Applying IEC 61439 to Lanshan Low Voltage Switchgear<\/h2>\n\n\n\n