| Voltage class and equipment type | Define rated voltage, frequency, continuous current, short-circuit withstand requirements, and whether the project needs low-voltage assemblies or medium-voltage metal-enclosed switchgear. | IEC 61439 applies to low-voltage switchgear and controlgear assemblies, generally up to 1,000 V AC or 1,500 V DC. IEC 62271-200 covers AC metal-enclosed switchgear above 1 kV and up to 52 kV. | Confirm that site-system voltage and fault levels are within the equipment ratings. Allow for access, cable entry, lifting, and replacement of major components. | Request rating schedules and type-test documentation for the exact product configuration and project voltage—not only a general product catalogue. |
| Short-circuit performance | Specify the prospective fault current, required short-time withstand duration, peak withstand current, and the protection-clearing assumptions used in the design. | Applicable IEC product standards and project-specific power-system studies. | Coordinate switchgear ratings with upstream and downstream protection. Installation changes to busbars, protective devices, or enclosure arrangements can affect the evaluated configuration. | Check that test evidence and rating declarations correspond to the offered assembly, including busbar arrangement and protective-device combination. |
| Internal arc protection | Determine whether internal-arc classification is required, the accessible sides to be protected, and the expected installation arrangement. | IEC 62271-200 includes internal-arc classification (IAC) for applicable medium-voltage metal-enclosed switchgear. | Follow the tested installation conditions, including room layout, pressure-relief direction, ventilation, and clearances. An IAC designation does not remove the need for site-specific safety controls. | Ask for the test report or classification details and verify that the tested configuration matches the proposed lineup and installation conditions. |
| Enclosure protection and environment | State required ingress-protection level, indoor or outdoor use, ambient conditions, altitude, humidity, dust, corrosion exposure, and any seismic requirements. | IEC 60529 defines IP-code classifications. Equipment environmental limits and other performance requirements should be checked against the applicable product standard and project specification. | Higher protection levels or harsh environments may affect cooling, condensation control, access, and maintenance. Confirm any altitude-related rating adjustments with the equipment supplier. | Verify that the stated IP rating applies to the complete installed assembly, including doors, cable interfaces, ventilation openings, and accessories. |
| Switching technology | Compare the proposed circuit-breaker or switching technology, rated operating sequence, mechanical endurance, and service conditions against the duty cycle. | Relevant IEC 62271 product standards for medium-voltage switching devices; IEC 60947 series for applicable low-voltage devices. | Maintenance tasks and intervals depend on the device design, operation count, switching duty, environment, and manufacturer instructions. Do not assume all technologies have identical service needs. | Confirm local availability of trained service personnel, compatible spares, specialist tools, and end-of-life handling instructions. |
| Protection, metering, and control | Document protection functions, instrument-transformer requirements, metering accuracy, trip and alarm signals, interlocks, and control-power arrangements. | Use the applicable device standards and the project’s protection, control, and measurement specifications. | Provide approved settings, coordination studies, wiring diagrams, and commissioning tests. Check compatibility with the site control system and communication architecture. | Request configuration files, settings documentation, communication-protocol details, and a clear process for software or firmware support. |
| Standards and conformity evidence | Identify the standards and editions required by the project and destination market; request declarations, routine-test records, and relevant type-test evidence. | IEC 61439, IEC 62271-200, IEC 60529, and applicable local electrical codes or conformity schemes, as relevant to the equipment and market. | Ensure drawings, labels, safety instructions, and commissioning documents meet local regulatory and language requirements. | Check document authenticity, scope, issuing body, product coverage, and whether the supplied configuration is within the evidence provided. |
| Factory testing and inspection | Agree on inspection hold points, routine tests, witness testing, acceptance criteria, documentation, and non-conformance procedures before production. | Applicable product-standard routine tests and the approved project inspection and test plan. | Review test records before shipment and resolve identified issues while the equipment remains accessible at the factory. | Clarify who pays for inspections, how test deviations are handled, and what records are included in the final handover package. |
| Shipping and logistics | Confirm package dimensions and mass, transport orientation, shock and moisture protection, lifting points, and whether the lineup ships assembled or in sections. | Project logistics requirements, supplier packing instructions, and applicable transport and customs rules. | Plan unloading equipment, temporary storage, indoor protection, and the route from delivery point to the electrical room. | Agree on Incoterms, insurance, export packing, customs documentation, spare-parts shipment, and responsibility for transit damage. |
| Site installation and commissioning | Obtain approved foundation and anchoring details, cable termination drawings, inter-panel connection instructions, and commissioning procedures. | Manufacturer installation instructions, project electrical design, and applicable local codes. | Check room readiness, earthing, ventilation, cable access, working clearances, and required lifting provisions. Verify wiring, mechanical operation, protection settings, and interlocks before energization. | Confirm whether qualified local technicians are available and whether remote commissioning support, training, and site supervision are included. |
| Maintenance and lifecycle support | Request an equipment-specific maintenance plan, recommended inspection tasks, consumable lists, spare-parts catalogue, and end-of-life guidance. | Manufacturer maintenance instructions, applicable standards, site safety procedures, and the owner’s maintenance policy. | Set maintenance frequency according to the equipment manual, operating duty, environment, inspection findings, and condition-monitoring results. Isolate and verify safe working conditions before service. | Check long-term spare-parts availability, service response coverage, warranty terms, technician training, and support for obsolete components. |
| Commercial and supplier evaluation | Compare total installed and lifecycle cost, scope boundaries, delivery schedule, warranty exclusions, service commitments, and payment milestones. | Project procurement documents and contract terms; there is no single technical standard that determines commercial suitability. | Include installation, testing, training, commissioning, expected maintenance, and critical spares when evaluating cost—not only the equipment purchase price. | Assess documented project experience, quality processes, financial and delivery capacity, local service coverage, and the clarity of contractual responsibilities. |
