| Ingress Protection | Use IP54 or higher for protected outdoor locations. Consider IP65 or IP66 where the enclosure may be exposed to water jets, dust, or severe weather. The required rating should match the installation environment. | IEC 60529: Degrees of protection provided by enclosures. | Third-party or witnessed IP test report, test configuration, enclosure drawings, gasket specification, and door-sealing details. | Confirm whether the selected IP rating remains valid after cable glands, ventilation units, meters, doors, and field modifications are installed. | Critical |
| Electrical Safety and Assembly Design | Low-voltage assemblies should be designed and verified for rated current, short-circuit withstand, temperature rise, clearances, creepage distances, and protective-circuit continuity. | IEC 61439-1 and the applicable product part of the IEC 61439 series. | Design verification records, routine test forms, single-line diagrams, rated data sheet, and protective conductor continuity results. | Check whether the manufacturer can revise busbar layouts, feeder numbers, component positions, and cable-entry arrangements without weakening verification coverage. | Critical |
| Medium-Voltage Metal-Enclosed Construction | For medium-voltage switchgear, verify compartmentalization, internal arc classification where required, mechanical interlocks, earthing arrangements, and pressure-relief provisions. | IEC 62271-200 for AC metal-enclosed switchgear and controlgear above 1 kV and up to 52 kV. | Type-test certificates, internal arc classification, rated voltage and current data, interlock drawings, and factory inspection records. | Confirm the available range of busbar sections, withdrawable or fixed modules, cable compartments, relay panels, and environmental options. | Critical |
| Enclosure Material and Corrosion Resistance | Material selection should reflect humidity, salt exposure, chemicals, ultraviolet radiation, and mechanical impact. Outdoor projects commonly require coated steel, stainless steel, or aluminum according to the site conditions. | Coating performance may be assessed using ISO 9227 salt-spray testing and the specified coating system requirements. | Material certificates, coating-system description, paint thickness records, adhesion results, corrosion-test reports, and surface-preparation procedure. | Evaluate the supplier’s ability to provide marine-grade finishes, stainless fasteners, sealed hinges, drainage design, and replacement coating options. | High |
| Water Management and Condensation Control | A waterproof enclosure must also control condensation. Good designs use sloped surfaces, drainage paths, sealed cable entries, anti-condensation heaters, thermostats, and suitable ventilation or pressure-equalization methods. | Project environmental specification, IEC 60529, and the manufacturer’s validated design procedures. | Internal layout drawings, drainage details, heater and thermostat ratings, cable-gland schedule, and condensation-risk assessment. | Ask whether the supplier can adapt drainage, heater control, cable-entry orientation, and rain-canopy design to local climate conditions. | High |
| Electrical Ratings | Verify rated operational voltage, insulation voltage, frequency, busbar current, short-time withstand current, peak withstand current, and prospective short-circuit level against the project specification. | Applicable IEC 61439 or IEC 62271 requirements and the approved project specification. | Technical data sheet, calculation package, type-test evidence, nameplate sample, and protection-coordination information. | Check the available rating combinations and whether non-standard current, voltage, frequency, or short-circuit requirements can be engineered and verified. | Critical |
| Factory Acceptance Testing | Routine verification should cover wiring, protective circuits, insulation, dielectric performance where applicable, mechanical operation, functional interlocks, and control-system operation. | IEC 61439 routine verification or IEC 62271 routine tests, depending on equipment type. | Approved inspection and test plan, signed FAT reports, calibration certificates, punch-list records, and customer-witness procedure. | Confirm the supplier can support remote or on-site FAT, staged inspections, multilingual documentation, and customer-specific test sequences. | Critical |
| Component Traceability | Every major device should be identifiable by part number, rating, revision, and production batch. Traceability should extend to busbars, insulation materials, terminals, relays, breakers, and enclosure components. | Manufacturer quality-management procedures and project quality plan. | Approved bill of materials, incoming-inspection records, serial-number register, material certificates, and change-control history. | Assess whether equivalent components require prior approval and whether substitutions are formally documented before production. | High |
| Customization Capability | Common customization areas include enclosure dimensions, cable-entry direction, busbar arrangement, feeder quantity, metering, protection relays, communication protocols, labels, and local code requirements. | Approved design drawings, project specification, and applicable IEC standards. | Previous anonymized drawings, engineering-change procedure, 3D or fabrication drawings, wiring diagrams, and sample customization schedule. | Prefer suppliers with in-house electrical design, sheet-metal fabrication, busbar processing, wiring, programming, and final assembly. | High |
| Manufacturing Process Control | Key processes should include controlled cutting, bending, welding or fastening, surface treatment, busbar preparation, torque control, wiring inspection, sealing, and final functional testing. | Documented quality-management system, process-control plan, and applicable IEC verification requirements. | Process flow chart, inspection checkpoints, torque records, calibration list, nonconformance reports, and corrective-action records. | Factory visits should verify that critical processes are performed in-house rather than relying entirely on uncontrolled subcontracting. | High |
| Production Capacity and Delivery Control | Capacity should be judged by verified production resources, engineering workload, test-bench availability, material lead times, and documented on-time delivery performance—not by a stated annual output alone. | Project schedule, capacity plan, procurement plan, and production-control procedure. | Manufacturing schedule, critical-component lead-time list, production-area photos or audit findings, shipment records, and recovery plan for delays. | Confirm the supplier can separate prototype, standard, and mass-production workflows while maintaining the same quality controls. | Important |
| Documentation and Export Support | A complete supply package normally includes approved drawings, wiring diagrams, manuals, test reports, certificates, packing lists, spare-parts lists, and maintenance instructions. | Project documentation requirements and destination-country electrical regulations. | Sample document index, revision-control procedure, English technical files, export packing specification, and certificate-management process. | Check support for metric or imperial dimensions, local labeling, destination voltage systems, customs documents, and remote commissioning. | High |
| Warranty and After-Sales Service | Commercial terms should define warranty duration, response time, replacement-part availability, remote troubleshooting, field-service scope, and exclusions related to incorrect installation or environmental misuse. | Purchase contract, project quality plan, and agreed service-level terms. | Warranty template, service-response procedure, spare-parts matrix, escalation contacts, and anonymized service records. | Evaluate the supplier’s ability to provide commissioning guidance, troubleshooting in English, replacement enclosures or components, and long-term technical support. | Important |
| Overall Supplier Qualification | A strong candidate should satisfy the required electrical ratings, environmental protection, testing, documentation, customization, and delivery conditions simultaneously. The lowest price should not replace technical verification. | Project-specific compliance matrix combining applicable IEC standards, local regulations, and purchaser requirements. | Completed technical questionnaire, compliance matrix, test evidence, factory-audit report, reference project documentation, and signed deviation list. | Use a weighted evaluation model: technical compliance 35%, waterproof and corrosion performance 20%, manufacturing control 15%, customization 10%, delivery 10%, service and commercial terms 10%. | Critical |
