An inspection and test plan (ITP) turns a specification into a controlled sequence of evidence. A weak ITP lists “check switchgear” and “FAT” without criteria, responsibility or hold points. A professional ITP identifies the exact characteristic, governing clause/drawing, test object, method, acceptance, record and who may release the next stage.
This guide provides a risk-based method for building an MV switchgear ITP from incoming material through fabrication, assembly, IEC routine tests, project FAT, packing and dossier release. It includes hold/witness/review points, sampling, calibration, readiness gates, nonconformity and a practical matrix aligned with IEC 62271-1 and IEC 62271-200.
Executive conclusions
- Build the ITP after a requirement traceability matrix identifies every contractual, regulatory, IEC and approved-drawing requirement.
- One ITP row should describe one auditable activity or logically inseparable group with a clear acceptance criterion.
- Cite the exact governing document/edition/clause/drawing and approved procedure; “IEC 62271” is too broad.
- Distinguish type-test evidence review, mandatory routine testing, special tests and project FAT demonstrations.
- Assign manufacturer perform/record responsibility independently of customer or third-party witness.
- Use hold points sparingly at irreversible/high-risk gates; excessive holds delay production and encourage informal waivers.
- Sampling applies only where the standard/contract permits it and must define population, method, traceability and escalation after failure.
- FAT readiness is a hold gate: construction, internal routine tests, approved documents/configuration and test-equipment status must be complete.
- Every NCR requires containment, disposition, retest and regression scope before release.
- The ITP closes only when signed records, serial traceability, calibration, deviations, as-left configuration and packing/dossier evidence are complete.
1. Inputs to the ITP
- purchase order, technical specification and approved deviations;
- applicable national/regulatory requirements;
- contracted IEC 62271-1/200 and component-standard editions/amendments;
- approved data sheets, ratings, classifications and type-test requirements;
- general arrangement, single-line, schematics, terminal/cable/earthing drawings;
- approved BOM, component/manufacturer list and quality plan;
- protection/control philosophy, trip matrix, settings, I/O, SCL/network/time files;
- manufacturer procedures, work instructions and routine-test plans;
- special/customer tests and acceptance limits;
- packing, transport, preservation, storage and final dossier requirements.
Create a requirements traceability matrix first. Each requirement maps to design evidence, manufacturing control, inspection/test or document review. The ITP should not compensate for an unresolved technical specification.
2. Anatomy of one ITP row
| Field | What good looks like |
|---|---|
| Activity/characteristic | “Measure protective-circuit continuity from each panel PE point to main earth bar” |
| Stage/location | Assembly/routine test/factory bay |
| Reference | Exact IEC clause + drawing/procedure revision |
| Method/equipment | Approved method, current/range and instrument class |
| Acceptance | Numerical/functional criterion and tolerance |
| Extent/sample | Every panel/point or defined sample |
| Responsibility | Manufacturer performer/inspector/approver |
| Customer/TPI point | H/W/R/S and notice period |
| Record | Named form/report and serial/configuration ID |
| NCR/release | Required action/authorization before next step |
3. Point codes
| Code | Definition | Control |
|---|---|---|
| H — Hold | Work cannot proceed without designated release/waiver | Written authorization; identify irreversible next step |
| W — Witness | Party invited to observe activity | Proceed after contractual notice if nonattendance is waived by terms |
| R — Review | Document/record submitted for review | Comments/approval workflow and due date |
| S — Surveillance | Party may inspect while work proceeds | Access and production schedule visibility |
| P — Perform/record | Manufacturer must execute and retain evidence | Not conditional on witness attendance |
Define the codes in the ITP legend. Some companies use different letters; the written meaning governs.
4. Risk-based point selection
- High consequence/hidden later: busbar joints, supports, internal partitions, earthing paths, CT polarity—use hold/witness or detailed records before closure.
- Irreversible/destructive: welding, painting, encapsulation, high-energy test—gate prerequisites and witness as justified.
- Design applicability: type-test evidence, IAC/LSC/PM/IP—use review hold before release of manufacture.
- Repeatable production: dimensional checks, torque, wiring—manufacturer perform with surveillance/sampling based on process capability.
- Every-unit standard obligation: routine tests—full manufacturer coverage, witness sample as agreed.
- Project software/configuration: settings/SCL/GOOSE/SCADA—configuration freeze and end-to-end witness.
Do not assign a customer hold point to every row. Reserve holds for decisions where proceeding would make verification impossible, unsafe or expensive.
5. Stage 1 — design and qualification
- approved ratings, single-line, GA and classifications;
- short-circuit/earthing/busbar/thermal/arc-pressure studies as applicable;
- type-test reports and characteristic-specific applicability/extension;
- breaker/switch/CT/VT/relay component compliance;
- protection/control logic, DC voltage drop and output contact duty;
- IP/IAC/LSC/PM/PI and service-condition alignment;
- deviations and design-review closure;
- released manufacturing drawings/BOM and critical characteristics.
A design-release hold before procurement/fabrication prevents the factory from manufacturing a configuration whose type-test or interface evidence is still unresolved.
6. Stage 2 — supplier and incoming inspection
- approved supplier/part and purchase specification;
- material certificates for busbar/support/enclosure where required;
- breaker, CT/VT, relay, terminal and cable identity/ratings/serials;
- component routine/type certificates;
- damage, contamination, storage and shelf-life inspection;
- calibration/tool certificates for critical manufacturing processes;
- software/firmware version and cybersecurity provenance for IED/network devices;
- NCR/quarantine of substitutions or mismatched parts.
7. Stage 3 — enclosure fabrication and coating
- material grade/thickness and traceability;
- cut/bend/weld dimensions and weld procedure/inspection as required;
- doors, hinges, latches, partitions, shutters and relief components;
- surface preparation, coating system, thickness/adhesion/colour;
- bonding studs and paint-free/corrosion-protected interfaces;
- gasket, vent, fan/filter and gland-plate openings supporting IP design;
- internal-arc pressure/exhaust geometry preserved;
- dimensional release before equipment/bus assembly.
8. Stage 4 — primary and earthing assembly
- busbar material/section/plating, phase spacing and support span;
- joint preparation, hardware, torque and controlled witness mark;
- barrier, boots, stress control and creepage/clearance configuration;
- main earthing bar, panel joints, door/plate/rail bonds and PE terminals;
- breaker/disconnector/earthing-switch alignment and interlocks;
- CT/VT orientation, ratio/tap, phase/polarity and earth points;
- cable termination supports, phase clearance and test access;
- foreign-material/tool control before closing compartments.
9. Stage 5 — secondary/LVC assembly
- device/relay/PSU/switch part, firmware and mounting;
- AC/DC branch protection and segregation;
- wire section/colour/marker/ferrule/torque or spring insertion;
- terminal type, bridge/fuse/test block and PE rail construction;
- CT shorting and VT isolation/test sequence;
- trip/close paths, anti-pumping, TCS and dual-channel independence;
- EMC routing, screen, PE/FE and door loop;
- settings, I/O, SCL/network/time configuration load and checksum;
- point-to-point and pre-energization inspection.
10. Stage 6 — IEC routine tests
List each required IEC 62271-1/200 routine test as a separate or controlled group. Cite exact clauses and manufacturer procedures. Include:
- construction/design checks and identification;
- main/auxiliary circuit dielectric tests as applicable;
- main-circuit resistance where required;
- protective-circuit continuity/earthing verification;
- mechanical operation/interlocks/racking/shutters;
- control/protection/indication/wiring functions;
- gas/fluid pressure/tightness where applicable;
- post-test inspection and restoration;
- individual unit/serial result records.
The standard is the controlling source; this overview does not replace its test list or acceptance criteria.
11. Stage 7 — project FAT
- FAT readiness hold: internal tests complete and documents/configuration released;
- visual/dimensional/component/nameplate inspection;
- witnessed routine tests per approved sampling;
- full interlock matrix including negative/invalid sequences;
- protection relay injection, trip outputs and breaker operation;
- trip/close voltage, anti-pumping, TCS, 86 and breaker failure;
- CT/VT polarity/test facilities and safe isolation;
- SCADA alarms/SOE/controls and IEC 61850 GOOSE/network failover;
- DC/AC auxiliary loss, redundancy and degraded states;
- special/customer-specific tests;
- as-left restoration, NCR/punch and closing meeting.
12. Example ITP matrix
| No. | Activity | Reference | Extent | Mfr | Customer | Record |
|---|---|---|---|---|---|---|
| 1 | Type-test applicability review | IEC 62271-1/200 + report matrix | Design | P/R | H/R | Approved applicability statement |
| 2 | Bus joint before compartment closure | Drawing/work instruction | 100% | P | W/S | Torque/inspection sheet |
| 3 | CT polarity/core/tap | IEC 61869 + CT schedule | 100% | P | W sample | Serial/polarity report |
| 4 | Main-circuit dielectric routine test | Exact IEC clause/procedure | Every assembly | P | W sample | Individual test report |
| 5 | Interlock functional matrix | IEC/drawing/FAT procedure | Every function; witness scope defined | P | W/H critical | Signed matrix |
| 6 | Settings/SCL checksum | Approved configuration register | Every IED/file | P | R | Baseline register |
| 7 | Packing release | Packing specification | Every shipment unit | P | H/R | Release/photos/list |
13. Sampling rules
- State population: panels, breakers, joints, wires, functions or documents.
- State sample size and selection method (random, first article, worst case, each design variant).
- Do not sample mandatory every-unit routine tests.
- Witness sampling does not reduce manufacturer test coverage.
- Trace result to exact serial/configuration.
- Define escalation: if one sample fails, expand to all affected population and open NCR.
- Review process stability/change: new operator, tool, supplier or design may reset sampling confidence.
14. Calibration and test competence
- test equipment register with range, accuracy/uncertainty and calibration validity;
- traceability appropriate to contractual/laboratory requirements;
- competent authorized test personnel;
- controlled test software/templates and protection from unauthorized change;
- safe leads/adapters and pre-use checks;
- environmental conditions recorded where relevant;
- out-of-tolerance instrument impact assessment;
- ISO/IEC 17025 accredited laboratory only where required/appropriate, not assumed from calibration sticker alone.
15. Notification and witness logistics
- notice period, time zone, factory address and daily test schedule;
- prerequisite readiness package sent before travel;
- safety induction/PPE/access and energized/high-voltage boundaries;
- language, interpreter and document availability;
- remote-witness method only if contract permits and coverage/data integrity is adequate;
- right to waive witness in writing without waiving test requirement;
- rules for photography, cybersecurity and confidential data;
- stop-work authority and dispute/escalation route.
16. NCR, retest and release
- Record requirement, evidence, affected serials and immediate containment.
- Classify criticality and stop/hold downstream work as necessary.
- Determine root cause and population impact.
- Approve rework, repair, use-as-is concession or rejection.
- Define failed-test repetition and regression tests.
- Verify corrective action and record final results without deleting failure history.
- Update drawings/BOM/configuration/ITP if the fix changes them.
- Obtain authorized closure before shipment hold release.
17. Packing and final dossier stage
- all breakers/withdrawable parts identified, secured and in specified position;
- test grounds/jumpers/forces removed and covers fitted;
- transport locks, lifting points, centre of gravity and handling marks;
- desiccant/moisture barrier and storage duration/environment;
- loose parts, spares, tools and accessories listed/packed;
- shipping split, bus/link/earth parts and match marks;
- signed routine/FAT/NCR/calibration/configuration records;
- as-built documents/manuals and outstanding-document transmittal;
- final customer/quality release.
Common mistakes
- Copying an old ITP without requirement traceability.
- Citing “IEC 62271” without part, edition, clause or criterion.
- Making the customer witness responsible for performing mandatory tests.
- Using hold points on every row and waiving them informally.
- Sampling every-unit routine obligations.
- Starting FAT before internal test/configuration readiness.
- Using “OK” with no reading, serial or instrument ID.
- Not defining escalation after a sampled failure.
- Closing NCR without regression testing.
- Omitting packing/as-left configuration from the ITP.
Official standards and primary references
- IEC 62271-1:2017+AMD1:2021 — current common test and manufacturing requirements.
- IEC 62271-200:2021+AMD1:2024 — current metal-enclosed MV switchgear assembly requirements/tests.
- IEC 62271-100:2021+AMD1:2024 — current circuit-breaker test requirements.
- IEC 61869-1:2023 — current instrument-transformer general test requirements.
- IEC 60255-1:2022 — current protection-equipment test requirements.
- ISO/IEC 17025:2017 — current laboratory competence/calibration framework where applicable.
- IEC 61082-1:2014 — electrotechnical documentation rules supporting controlled FAT records.
Engineering note: An ITP is successful when every release decision can be reconstructed later: requirement, test object, method, measured evidence, reviewer and authorized progression are all traceable.