Episode 45 ~2:10 MV Switchgear EN · العربية

FAT, SAT & witness testing, three checkpoints, three signatures

FAT happens at the factory before shipping. SAT happens on site before energisation. Witness testing happens whenever the consultant wants to verify. Three checkpoints, and every Saudi tender requires all three. Skip any and the contractor pays.

Animated explainer, press play to watch the concepts now; the filmed cut publishes once production wraps.

What you'll walk away with

Four ideas to carry into the next specification conversation you have.

01

FAT, at the factory, before shipping.

Switchgear panel powered up at the manufacturer's facility. Functional tests, dielectric tests, primary injection. Consultant flies in to witness. Sign-off unlocks the shipping permit.

02

SAT, on site, before energisation.

Same panel, now installed, before live voltage. Insulation resistance, continuity, polarity, function checks. The contractor's responsibility to deliver.

03

Witness testing, verification at key milestones.

Cable termination witness, busbar torque witness, gas density witness. Spot checks the ITP demands at specific points in the build.

04

All three reports + ITP signed = handover certificate.

Without all three, the consultant doesn't sign the substantial completion certificate. No SCC = no final payment. That's why each is non-negotiable.

FAT vs SAT vs Witness, checkpoint matrix

What's verified at each stage. Saudi commercial tender baseline.

Test Location · timing Owner / consequence
FAT, Factory AcceptanceManufacturer · pre-shipManufacturer / unlocks shipment
SAT, Site AcceptanceProject site · pre-energiseContractor / unlocks live test
Witness Test, terminationsProject site · key milestonesContractor / unlocks next phase
Routine test (per IEC 61439-1)Manufacturer · every panelManufacturer / quality gate
Energisation / commissioningProject site · post-SATContractor + utility / live
Performance test (90-day)Project site · post-handoverOperator / warranty trigger
KSA Civil Defense audit (life safety)Project site · pre-occupancyAuthority / occupancy permit

Designing a fool-proof ITP

Five things every Saudi Inspection & Test Plan must include.

Test reference + standard for every line item.

Each test in the ITP must cite the standard (IEC 61439-1 §10.10 for temperature rise, IEC 60204-1 for insulation, etc.). Consultants reject ITPs that say 'manufacturer's recommended test'. Cite the clause.

Hold points vs witness points.

Hold point = contractor cannot proceed without consultant sign-off. Witness point = consultant may attend; absence doesn't block progress. Mix them right: too many holds = delay; too few = quality slip.

Acceptance criteria with numbers.

'Insulation resistance shall be acceptable' = vague. 'Insulation resistance ≥ 1000 MΩ at 1000 V DC, 60-sec hold' = enforceable. Numbers prevent post-hoc arguments.

Witness party identified by role, not name.

ITP says 'witnessed by Consultant'. Not 'witnessed by Eng. Ahmed', Ahmed may rotate out, take leave, or change firms. Role-based assignment survives staffing changes.

FAT-to-SAT traceability matrix.

Every FAT line has a corresponding SAT line. If FAT verified temperature rise, SAT doesn't need to re-verify (impossible without 8-hour live load). But continuity, insulation, polarity, re-verified on site. Build the traceability matrix during the ITP review.

Next Episode

Commissioning vs Energisation

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