Most factory acceptance tests are a demonstration. The equipment works, everyone watches it work, the certificate is signed, and the problems appear at site anyway. That is not bad luck. It is an agenda that tested the wrong things.
Start from what is already guaranteed. IEC 61439-1 requires routine verification on every low voltage assembly before it leaves the works — construction, dielectric properties, protective measures and continuity of the protective circuit. IEC 62271-200 imposes its own routine tests on every medium voltage cubicle. The manufacturer performs these whether you attend or not, and the records exist either way.
So a FAT that consists of watching routine verification being repeated has bought you nothing but travel. The value is in the second category: everything that is specific to your order and therefore outside the scope of any standard test.
| Already covered by routine verification | Only a FAT will catch it |
|---|---|
| Dielectric withstand | Protection settings against your coordination study |
| Continuity of the protective circuit | Interlock logic tested in the failure direction |
| Wiring against the manufacturer’s own schematic | Wiring against your approved schematic, at the latest revision |
| Device operation | Device catalog numbers against your approved vendor list |
| Degree of protection of the design | Degree of protection at the cable entries with the glands you will actually use |
| Marking per the standard | Labelling in your own tag convention, in both languages if the site needs it |
Set the acceptance criteria before you book the flight
A test with no written pass criterion cannot be failed, and a test that cannot be failed is a demonstration. Three documents have to be agreed and issued before travel, not produced on the day:
- The inspection and test plan, listing each activity, the acceptance criterion, the reference document and who signs.
- The approved drawing set at a stated revision. Half of all FAT disputes are two parties holding different revisions of the same schematic.
- The punch list procedure — what counts as category A (must be closed before shipment) against category B (closeable at site), and who decides. Agreeing this while standing in the test bay guarantees it is agreed badly.
The order of the day
Documentation first, before anything is energized
Review the design verification evidence and the routine verification records for the serial numbers in front of you. Check the device list against the approved vendor list, item by item, including the components nobody looks at — terminal blocks, auxiliary relays, surge protection. Confirm the drawing revision. This takes an hour or two and it is the highest-yield hour of the day, because every substitution and every revision mismatch surfaces here rather than after eight hours of testing.
Visual, dimensional and mechanical
Physical dimensions against the arrangement drawing, including transport split lines and the route into your switchroom. Paint and coating thickness against the specification. Cable entry arrangement with the actual gland plates. Busbar joint torque records — ask for the record and spot-check a joint against it; this is the single most commonly skipped item and the most common cause of a hot joint two years later. Door, shutter and withdrawal mechanics operated by hand.
Interlocks, tested in the direction that matters
Any interlock will pass if you test it by doing the permitted thing. An interlock is only proved by attempting the prohibited one: close the earth switch with the breaker in service position, withdraw with the breaker closed, open a compartment that should be locked. Work through the interlocking schedule attempting each forbidden operation. If the manufacturer has not been asked for an interlocking schedule, that is itself the finding.
Electrical
Point-to-point wiring checks against your schematic. Primary injection where the scope includes current transformers, secondary injection for the protection functions, and the trip circuits proved through to the breaker rather than to a terminal. Protection settings loaded and verified against the coordination study, with a printout retained. Where an IEC 61850 scheme is in scope, the communications are part of the test — GOOSE interlocking and reporting proved on the configured scheme, not deferred to site.
Functional and as-built
Full functional run of control, indication, alarms and any automatic transfer scheme, including the failure cases. Then labelling, nameplates, warning signage and the as-built marked up on the spot. Finish with the spares and special tools against the contract list — a missing racking handle is a trivial item that stops a commissioning team dead.
What you should leave with
A signed test report referencing the inspection and test plan activity by activity. The routine verification records for the serial numbers tested. Protection setting printouts. Torque records. The punch list with categories, owners and dates. The as-built marked drawings. Photographs of the internal arrangement before the covers go back on — these are worth more than anyone expects two years into operation, when somebody needs to know what is behind a barrier without taking an outage.
Where we stand
Witnessed testing is carried out in Madinah, and the inspection and test plan is issued for agreement before the date is fixed rather than presented on the day. Routine verification records are kept against serial numbers, and the interlocking schedule is produced as a deliverable so that interlocks can be tested in the failure direction rather than demonstrated in the permitted one. Our quality management system is certified to ISO 9001:2015; the certificate and the test record formats are issued on request against a named enquiry.