Switchgear tests answer different questions. Type tests qualify a design, routine tests verify every manufactured unit where required, and special tests are additional agreed investigations. FAT demonstrates contract compliance but does not redefine those categories.

Learning objectives

Classify each test correctly, request applicable evidence and prevent destructive design tests from being repeated as routine FAT activities.

Core engineering principles

Type tests support a design and rating envelope

Dielectric, temperature-rise, short-circuit and internal-arc tests are performed on representative configurations under defined extension rules.

Routine tests apply to manufactured equipment

They check workmanship, dielectric integrity, mechanical operation and functional correctness on the supplied units as required by the product standard.

Special tests are contractually agreed

They may investigate unusual service conditions or customer requirements and need a defined method and acceptance criterion.

FAT is an acceptance event

It witnesses selected inspections and functions against approved documents. Sampling during FAT does not cancel routine-test obligations.

Test evidence has scope

Report rating, arrangement, components, laboratory and edition must cover the supplied configuration.

Engineering application method

  1. Step 1: List applicable product standards and contract editions.
  2. Step 2: Map each requirement to type, routine, special or FAT evidence.
  3. Step 3: Review report scope and design extensions.
  4. Step 4: Complete routine testing before customer FAT.
  5. Step 5: Record deviations without relabelling test categories.

Practical example

An internal-arc test cannot be repeated on each panel during FAT. The manufacturer supplies applicable type-test evidence while FAT verifies the supplied construction and routine-test records.

Common mistakes

  • Calling every FAT check a routine test.
  • Sampling routine tests without contractual basis.
  • Requesting destructive type tests on production panels.
  • Accepting a certificate without configuration scope.
  • Mixing IEC and IEEE acceptance values selectively.

Design and review checklist

  • What question does each test answer?
  • Is it design or unit evidence?
  • Which panels require routine coverage?
  • Does type evidence cover the supplied variant?
  • Are special tests contractually defined?

Standards basis and official sources

Engineering note: Verify the contracted standard edition, amendments, manufacturer evidence and project-specific studies before applying these principles to a supplied assembly.

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