IEC 61439 design verification for an assembled LV switchboard

Use Part 1 with the relevant product part

This note references GB/T 7251.1-2023 and GB/T 7251.2-2023, and IEC 61439-1:2020 and IEC 61439-2:2020. General rules are used with the applicable product part. For a power switchgear and controlgear assembly, clarify the Part 2 scope if the submitted report cites only Part 1.

Identify the verified design

Ask who the original manufacturer is, which verified design is being used and what the panel builder has changed. The review covers the busbars, enclosure, protective circuits, clearances, creepage distances, component interaction, temperature rise and short-circuit withstand.

For component substitutions, rating increases, different separation arrangements or ventilation changes, request the applicable verification route and supporting documents. Record accepted deviations against the drawing revision.

Check the loading assumptions

Temperature-rise review needs the circuit loading, diversity assumptions, component losses, enclosure dimensions, ventilation and ambient conditions. Ask how the offered circuit schedule fits the verified design and the relevant group rated current assumptions. Include high ambient temperature, altitude and harmonic-producing loads in the design inputs.

Receive a record for each completed switchboard

Design verification establishes the characteristics of the design using the permitted verification methods. Routine verification checks each completed assembly. Request these as separate deliverables, with the delivered switchboard identified on its inspection and test sheet.

Agree which records the buyer will review or witness during FAT. Keep the final circuit schedule, drawing revision, design-verification reference and signed routine-verification sheet together in the delivery file.