Routine tests and a Factory Acceptance Test are not synonyms. IEC 62271 product standards define test categories and require routine tests on manufactured equipment. “FAT” is normally a contractual acceptance event: it may witness selected routine tests, add functional demonstrations, verify documents/configuration and close deviations before shipment. The IEC standard does not create one universal FAT script.
This guide explains the boundary between routine testing and FAT for MV metal-enclosed switchgear. It covers type and special tests, test responsibility, witness/hold points, sampling, calibrated equipment, acceptance criteria, nonconformities, release dossiers and practical planning under IEC 62271-1:2017+A1:2021 and IEC 62271-200:2021+A1:2024.
Executive conclusions
- Routine tests are product-standard/manufacturer obligations applied to each manufactured unit or assembly as specified; customer attendance does not create or remove that obligation.
- FAT scope comes from the purchase specification, approved inspection and test plan (ITP), procedures and applicable standards.
- A FAT can witness routine tests, but an unwitnessed routine test with valid records remains a routine test; conversely, a demonstration at FAT is not automatically an IEC routine test.
- Type tests establish design performance on representative test objects. They are normally reviewed as applicable evidence, not repeated on every order.
- Special tests are by agreement and must define test object, method, acceptance criterion, responsibility, risk and cost before manufacture.
- Do not use “FAT passed” to hide incomplete mandatory routine tests, open nonconformities or unapproved configuration.
- Witness/hold/review points must state notice, prerequisites, acceptance criteria, right to waive and action if the customer is absent.
- Use calibrated/traceable instruments with range, uncertainty and validity appropriate to each result; record serial number and calibration status.
- Freeze drawings, settings, firmware, SCL and bill of materials before FAT so the tested configuration is identifiable.
- Shipment release is a controlled commercial/quality decision after tests, documentation and punch items—not merely the moment the final demonstration ends.
1. The four concepts
| Concept | Purpose | Typical test object | Basis |
|---|---|---|---|
| Type test | Verify design characteristics/performance | Representative design/test object | IEC product standard and design applicability |
| Routine test | Reveal manufacturing/material defects and verify each supplied item as specified | Every produced unit/assembly under the standard | IEC product standard/manufacturer procedure |
| Special test | Verify additional agreed characteristic | Defined sample/unit/assembly | Agreement between manufacturer and user |
| FAT | Contractual pre-shipment acceptance/review event | Order equipment and documents/configuration | Contract, ITP, approved FAT procedure |
A single activity can belong to more than one planning context. For example, a power-frequency withstand test can be a mandatory routine test and also a witnessed FAT item. Its IEC category remains routine; “FAT” describes the acceptance event.
2. What routine tests establish
Routine tests are intended to reveal faults in material/workmanship and confirm specified characteristics of the manufactured equipment. The exact list, sequence and limits must be taken from the contracted IEC editions and the relevant component standards.
- dielectric tests on the main circuit and auxiliary/control circuits as applicable;
- measurement/verification of main-circuit resistance where required;
- design/construction checks against drawings and ratings;
- mechanical operation, interlocks, position and control functions;
- protective-circuit continuity/earthing verification;
- gas/fluid tightness/pressure checks for applicable designs;
- wiring, indication, measurement, protection and functional checks;
- component routine-test evidence where the assembly standard relies on the component standard.
This list is an engineering overview, not a substitute for the standard’s clauses. IEC 62271-200 supplements IEC 62271-1 for the complete metal-enclosed assembly, while circuit breakers, disconnectors, earthing switches, instrument transformers and protection IEDs have their own standards.
3. What FAT adds
- approved-drawing/BOM/nameplate/component inspection;
- review of type-test evidence and design applicability;
- witness of selected routine tests;
- functional protection/control/interlocking/SCADA/IEC 61850 demonstrations;
- project-specific settings, I/O, trip matrix, alarms and SOE checks;
- dimensional/interface/cable-entry/serviceability inspection;
- document, firmware, SCL, switch and configuration baseline review;
- special/customer tests agreed in the purchase specification;
- nonconformance/punch-list closure or formal disposition;
- packing, preservation, spares and shipment-release readiness.
Many of these are vital but are not IEC routine tests. Label them correctly so acceptance criteria and responsibility are clear.
4. Type-test evidence at FAT
Type tests can be high-energy, destructive or impractical on production equipment: short-time/peak withstand, temperature rise, dielectric/impulse, making/breaking, internal arc and mechanical/endurance tests are typical design-verification areas depending on product. FAT should review:
- test report/certificate issuer, laboratory and test object identification;
- standard edition, ratings and test arrangement;
- manufacturer/product family/design parameters;
- whether supplied configuration lies within report applicability/extension rules;
- differences in enclosure, compartment, conductor, breaker, CT/VT, busbar, ventilation, IAC or earthing design;
- deviations/conditions/limitations in the report;
- authorized engineering statement for any extension of validity;
- traceable report revision, not a marketing summary.
A physically similar panel is not automatically covered. Conversely, repeating a destructive type test on each order is not routine acceptance unless the contract expressly requires a new qualification.
5. Special tests by agreement
Special tests must be agreed early. Examples can include project-specific partial-discharge measurement, additional environmental/seismic/EMC tests, cable dielectric interfaces, extra mechanical cycles, site-specific functional scenarios or a new design qualification. For each special test define:
- purpose and governing document;
- test object/sample and whether it remains shippable;
- method, sequence, conditioning and safety boundary;
- test voltage/current/load/environment;
- measurement system/uncertainty;
- acceptance limits and statistical/sampling rule;
- witness/hold point and report format;
- risk of damage, repair and retest;
- cost/schedule and responsibility.
6. FAT scope hierarchy
- Purchase order/contract and approved technical specification.
- Mandatory national/regulatory requirements.
- Contracted IEC standards and amendments.
- Approved data sheets, drawings and deviations.
- Approved quality plan and ITP.
- Approved FAT procedures/check sheets.
- Manufacturer procedures/manuals within their declared applicability.
Resolve conflicts before FAT. An acceptance limit should never be invented beside an energized panel because two documents disagree.
7. Witness, hold, review and surveillance points
| Point | Meaning | Work progression |
|---|---|---|
| Hold (H) | Specified party authorization required | Do not proceed without written release/waiver |
| Witness (W) | Party invited to observe | May proceed after proper notice if contract permits absence |
| Review (R) | Records/documents submitted | Proceed according to approved review workflow |
| Surveillance (S) | Party may inspect during activity | No fixed hold unless issue found |
| Manufacturer perform/record (P) | Mandatory internal execution and record | Independent of customer attendance |
The ITP must define notice period, recipients, prerequisites, waiver procedure and consequence of missed notice. “Client not present” is not permission to skip a mandatory routine test.
8. Sampling and test object identification
- Mandatory routine-test coverage follows the product standard and cannot be reduced by an informal FAT sample.
- Customer-witness sampling may observe one panel while manufacturer records cover all panels.
- Functional scenarios may be sampled only with contractual/statistical basis and proven design/manufacturing repeatability.
- Identify lineup, panel, breaker, CT/VT and IED serial numbers in every record.
- If interchangeable breakers are sampled, verify every unit’s own routine records and interchangeability requirements.
- Mark repaired/retested units so their final accepted record is unambiguous.
- Never copy results from a representative cubicle into individual records.
9. Configuration freeze before FAT
- approved general arrangement/single-line/schematics/terminal plans;
- rated values/classifications/nameplates;
- released BOM and component serials;
- relay settings/logic and firmware;
- SCL/GOOSE/network switch/time configuration;
- SCADA point list, alarm text/priority and trip matrix;
- test procedure/version and test-set templates;
- open deviations/NCRs and permitted temporary configuration.
Record checksums/revisions. If a setting or drawing changes during FAT, perform impact analysis and regression testing; do not let the tested baseline become unknowable.
10. Test equipment and metrological control
- instrument/test-set ID, model, serial number and calibration due date;
- measurement range/resolution and uncertainty appropriate to the acceptance limit;
- traceability and competence under the organization’s quality system;
- pre-use visual/self-check and lead/accessory rating;
- environmental conditions where they affect the result;
- approved software/template version;
- raw readings plus corrected/final result where applicable;
- out-of-calibration investigation covering tests since last known valid state.
ISO/IEC 17025:2017 remains the current international laboratory-competence standard (confirmed in 2023). Accreditation may be contractually required for particular tests/calibrations; it is not automatically implied for every factory functional check.
11. Practical FAT sequence
- Readiness/document/configuration review.
- Opening meeting: scope, safety, lineup IDs, test order, deviations and witnesses.
- Visual/dimensional/component/nameplate inspection.
- Protective-circuit continuity and wiring/terminal checks.
- Mechanical operation, racking, shutters and interlocks.
- Mandatory electrical routine tests using approved sequence.
- Protection/control/SCADA/IEC 61850 end-to-end functional tests.
- Project special tests and degraded-state scenarios.
- Post-test inspection and restoration of links/settings/covers.
- Review results, NCRs/punch list and retest requirements.
- Closing meeting and conditional/final release decision.
- Compile signed test dossier and shipment/preservation records.
12. Example ITP extract
| Activity | IEC/contract category | Manufacturer | Customer | Evidence |
|---|---|---|---|---|
| Main-circuit dielectric | Routine test | Perform/record | Witness sample/as agreed | Individual result sheet |
| Protective continuity | Routine/assembly requirement | Perform/record | Witness | Measured points/results |
| Interlock functional matrix | Routine + project FAT | Perform | Witness/hold for critical cases | Signed matrix |
| Relay settings/SCL review | Project FAT | Submit/configure | Review | Revision/checksum |
| Internal-arc certificate | Type-test evidence | Submit applicability | Review | Report and deviation assessment |
| Special PD test | Special by agreement | Perform | Hold/witness | Approved method/raw/report |
13. Nonconformity, punch item and concession
| Record | Use | Required closure |
|---|---|---|
| Nonconformity (NCR) | Requirement not met | Correction/root cause/disposition/retest/approval |
| Punch item | Defined incomplete/minor item | Owner/date/evidence; classify shipment impact |
| Concession/deviation | Formal acceptance of departure | Authorized technical/commercial approval and as-built record |
| Observation | Potential improvement/no proven nonconformity | Review and response as contract requires |
Never relabel a failed mandatory result as a punch item to obtain shipment. Define whether repair requires repeat of the failed test and regression of adjacent tests.
14. FAT completion and shipment release
- all mandatory routine tests complete for every supplied item;
- witnessed/project tests accepted or formally dispositioned;
- failed/repaired items retested and traceable;
- temporary test links, grounds, settings, forces and bypasses removed;
- final configuration revisions/checksums recorded;
- type-test/applicability and component certificates complete;
- punch/NCR shipment status authorized;
- packing, desiccant, transport locks and storage instructions verified;
- spares/tools/manuals and final dossier issue plan agreed;
- release note signed by the authorized parties.
15. Minimum FAT dossier
- signed ITP/FAT attendance and equipment/serial register;
- individual routine-test reports;
- functional/interlock/protection/SCADA test sheets;
- special-test reports and raw data as specified;
- calibration/test-equipment register;
- approved drawings/BOM/settings/SCL/firmware/network baselines;
- type-test certificates/reports and applicability statement;
- component certificates/routine records where required;
- NCR/punch/concession and retest closure;
- photographs and as-left configuration/packing release.
Common mistakes
- Writing “FAT to IEC 62271” without a project FAT scope.
- Calling every customer demonstration an IEC routine test.
- Skipping mandatory routine tests because the customer did not witness.
- Trying to repeat destructive type tests on production panels without agreement.
- Reviewing a certificate without checking design applicability.
- Using representative-panel results as if every unit was tested.
- Changing settings/SCL during FAT without version control/regression.
- Using test equipment with expired or unsuitable calibration.
- Closing a failed requirement as a vague punch item.
- Signing shipment release before final records/restoration are complete.
Official standards and primary references
- IEC 62271-1:2017+AMD1:2021 — current common specifications and test-category framework for MV/HV switchgear.
- IEC 62271-200:2021+AMD1:2024 — current metal-enclosed MV switchgear assembly tests and requirements.
- IEC 62271-100:2021+AMD1:2024 — current circuit-breaker component test requirements.
- IEC 60255-1:2022 — current common requirements/tests for protection equipment.
- ISO/IEC 17025:2017 — current, 2023-confirmed requirements for competent testing/calibration laboratories where applicable.
- IEC 60529 consolidated edition — formal enclosure IP-code testing; visual FAT checks do not replace it.
Engineering note: Ask two separate questions: “Has every supplied assembly passed its required routine tests?” and “Has the contractually defined FAT demonstrated readiness for shipment?” A professional release needs both answers.