For an IEC 61439 switchgear RFQ, the buyer should define the assembly application, system ratings, fault level, installation conditions, internal separation, cable interfaces, component requirements and required verification records. Referring to IEC 61439 in the BOQ is useful, but it does not by itself define a complete low-voltage assembly.
This checklist helps EPC contractors and project buyers prepare comparable enquiries. Final requirements must follow the applicable IEC publications, project specification and approved electrical design.
Which IEC 61439 parts should be identified?
IEC 61439-1 contains the general rules for low-voltage switchgear and controlgear assemblies. It is used with the relevant assembly-specific part. For power switchgear and controlgear assemblies, IEC 61439-2 is commonly referenced. The required edition and any project amendments should be stated in the RFQ.
IEC 61439 procurement checklist
| RFQ item | Information to define | Why it matters |
|---|---|---|
| Assembly duty | Main distribution, motor control, transfer, compensation or another application | Establishes the functional scope |
| System data | Rated voltage, frequency, phases, earthing system and control voltage | Sets the electrical basis |
| Current ratings | Incomer, busbar and outgoing feeder ratings plus diversity and spare capacity | Defines the current-carrying requirements |
| Short-circuit duty | Prospective fault level, withstand value and duration where applicable | Coordinates the assembly and protective devices |
| Service conditions | Indoor or outdoor location, ambient temperature, altitude, humidity, dust and corrosion | Affects enclosure and thermal design |
| Enclosure | IP rating, access direction, dimensions and ventilation conditions | Defines protection and installation constraints |
| Internal arrangement | Required separation, fixed or withdrawable units and cable compartment arrangement | Supports operation and maintenance needs |
| Cable interfaces | Top or bottom entry, cable quantities, termination space and busduct interfaces | Prevents site-interface conflicts |
| Components | Approved makes, device series, protection, metering and communication | Creates a comparable component basis |
| Deliverables | Drawings, schedules, verification records, manuals, FAT and packing documents | Defines the handover package |
Design verification and routine verification
Design verification addresses whether the assembly design meets the applicable construction and performance requirements. Routine verification is performed on each completed assembly to check manufacturing and operation against the approved design. The RFQ should identify which records, declarations or supporting documents the supplier must provide.
Documents to issue with the RFQ
- Controlled single-line diagram
- BOQ, feeder schedule and cabinet references
- System and short-circuit data
- Project technical specification
- Room layout, cable entry and dimensional restrictions
- Approved component list or acceptable alternatives
- Inspection, FAT and documentation requirements
- Quantity, destination, packing and requested delivery schedule
Use the SLD and BOQ preparation guide to coordinate document references, and review BOQ vs RFQ when defining the enquiry package.
Equipment-specific additions
- MCC motor control centre: motor schedule, starting method, control philosophy and communication
- Automatic transfer switch panel: source ratings, neutral arrangement, transfer sequence and generator interface
- APFC capacitor bank panel: load profile, existing and target power factor, required kVAr and harmonic information
Questions to ask when comparing quotations
- Does the offered configuration match every SLD and BOQ reference?
- Which values remain assumptions or require confirmation?
- Are component substitutions clearly identified?
- What verification and routine-inspection documents are included?
- Are exclusions, site interfaces, packing and delivery boundaries stated?
Our published production and inspection basis is described on the quality and standards page. Order-specific records and witness requirements must be confirmed before production.
Frequently asked questions
Is stating IEC 61439 in a BOQ enough?
No. The buyer should also define ratings, fault level, installation conditions, separation, enclosure, components, interfaces and required documentation.
Does a switchgear model name prove IEC 61439 compliance?
No. Compliance relates to the completed assembly, its verified design basis, components, ratings and construction for the stated application.
What should be sent before requesting a quotation?
Send the SLD, feeder schedule, system ratings, fault level, project specification, component requirements, quantity and destination. Missing inputs can then be listed for clarification.
Should FAT requirements be stated in the RFQ?
Yes. State the required inspection scope, witness points, records and document format so they can be included in the technical and commercial offer.
Request a project-based quotation
Send the controlled drawings and technical requirements for an initial scope review before pricing.
Official references: IEC 61439-1:2020 and IEC 61439-2:2020.