A switchgear type-test report is the single most objective document in a procurement file. Price lists, brochures and sales decks can all be negotiated — but a type-test report records what a specific design actually survived in a laboratory. Knowing how to read one separates a buyer who assumes compliance from a buyer who verifies it.

This guide is written for B2B purchasers, EPC contractors and consulting engineers who specify medium-voltage switchgear and need to validate a supplier’s test documentation before signing off. It walks through the structure of a report, the seven items that matter most, and the red flags that should stop a purchase order.

Type test vs. routine test: why the distinction decides everything

The first thing to confirm is which kind of test the document describes. Confusing the two is the most common and most expensive mistake in switchgear procurement.

A routine test certificate is not a substitute for a type-test report. If a supplier hands you a one-page “test certificate” listing only wiring checks and a functional operation test, you are not looking at proof of design compliance — and you should ask for the full type-test report before proceeding.

The five fields on page one that do 80% of the work

Before reading a single measured value, verify the identity block on the cover page. In practice, most non-conformances are caught here, not in the test data.

1. Standard and edition. For factory-assembled metal-enclosed switchgear the governing document is typically IEC 62271-200 (or the equivalent national standard such as GB/T 3906). Note the edition year — a report issued against a 2003 edition does not automatically satisfy a specification calling for the 2021 edition, because test severities and IAC classifications changed.
2. Object under test. Exact type designation, rated voltage, rated current, rated short-time withstand current, frequency, and number of poles. Every field must match your enquiry.
3. Sample description and drawings. The report should reference drawing numbers, photographs of the sample, and a list of critical components (circuit breaker, instrument transformers, bushings, insulators). This is what later proves the tested unit was the same as the delivered unit.
4. Laboratory identity and accreditation. Name of the testing institute, accreditation body (e.g. CNAS, DAkkS, A2LA) and the accreditation scope. An accredited lab report carries far more weight than an in-house “factory test report”.
5. Report number, date and page count. A complete report on a full type-test programme typically runs to dozens of pages. A three-page document almost certainly is not a full type test.

The 7-point checklist for reading the test data

Once the identity block checks out, work through the technical clauses. These seven items cover what actually determines whether the switchgear is safe and fit for your application.

1. Dielectric (insulation) tests

Look for two separate withstand tests: power-frequency withstand voltage (typically 1 minute) and lightning impulse withstand voltage (typically 1.2/50 µs). Read them across three paths — phase-to-earth, phase-to-phase, and across the open switching device (isolating distance).

The numbers you read are usually given as rated values from the standard’s tables, with the applied test voltage in the same column. Confirm the applied value equals or exceeds the rated value for your rated voltage, and that no disruptive discharge occurred. Partial discharge measurement, where included, is a useful supplementary indicator of insulation quality.

2. Temperature rise test

This test proves the assembly can carry its rated current continuously without overheating. The report must state: the test current (usually rated current, sometimes 1.1× for certain assemblies), the ambient conditions, and the measured temperature rise of contacts, terminals and accessible surfaces.

Compare the measured values against the limits in the standard for each material and component type — bare copper contacts, bolted connections, silver-plated joints and insulating materials each have different permitted rises. A report that records only “passed” without the measured rises and the ambient baseline is incomplete.

3. Short-time withstand and peak withstand current (Icw / Ipk)

This is the clause that matters most for fault conditions in service. Verify:

• Icw (short-time withstand current) — the rms fault current the assembly survived, and the duration (1 s or 3 s are typical; the duration must be stated, because 25 kA/1 s is not equivalent to 25 kA/3 s).
• Ipk (peak withstand current) — normally 2.5 × Icw for 50 Hz systems, representing the electromagnetic forces on busbars and supports.
• Earthing circuit rating — the earth path must also carry a stated fault current for a stated duration; this is frequently overlooked.

The pass criteria are no permanent deformation, no welding of contacts, and successful verification afterwards by a dielectric test and a functional check. If the report omits the post-test verification, treat the result as incomplete.

4. Internal arc classification (IAC)

If personnel safety is in your specification, this clause is non-negotiable. An IAC classification states the accessible sides (e.g. A = front, F = front, L = lateral, R = rear), the arc fault current and the duration — for example “A FLR, 25 kA, 1 s”.

Read the accessible-side coding carefully: a classification restricted to “A” (front only) does not protect an operator standing at the rear of the cubicle. Also check whether the classification applies to the circuit-breaker compartment, the busbar compartment, the cable compartment or all of them, and whether pressure-relief ducting was fitted during the test. For a deeper treatment of how arc-fault containment is engineered, see our article on internal arc fault suppression in medium-voltage switchgear.

5. Enclosure protection degree (IP / IK)

Verify the IP code on the enclosure and, for withdrawable designs, whether the rating applies with the truck in the connected, test and disconnected positions. For outdoor or public-area installations, an IK rating for mechanical impact resistance is equally relevant. A mismatch here is one of the most common causes of premature insulation failure in humid or dusty environments.

6. Mechanical endurance and interlock verification

Check the number of operating cycles performed (the standard defines M1/M2 or E1/E2 classes for the switching device) and confirm the report includes verification of the safety interlocks: that the earthing switch cannot close on a live circuit, that the withdrawable truck cannot be racked in or out with the breaker closed, and that compartments cannot be opened while live. These interlocks are what prevent the majority of serious switchgear incidents.

7. Making and breaking capacity of the switching device

The assembly report covers the enclosure and busbar system, but the interrupting device is tested to its own standard. For vacuum circuit breakers that is IEC 62271-100. Confirm the breaker’s own type test covers the short-circuit breaking current and the rated operating sequence at your system voltage. If your assembly uses a withdrawable truck, an indoor vacuum circuit breaker of the same series as the tested sample is what keeps the combined assembly valid.

Red flags that should stop a purchase order

Watch for these — each one indicates the documentation does not actually cover what you are buying.

• Rating outside the tested envelope. You order 31.5 kA but the report only tested 25 kA, with no interpolation or extension report from the laboratory.
• Different type designation. The tested model differs from the quoted model by even one character, and no similarity/coverage report is provided.
• No independent laboratory. Only a self-declared factory test sheet with no accredited third-party involvement.
• Missing pages or annexes. The report jumps from page 1 to the conclusion, or oscillograms and photographs are absent.
• Expired or superseded edition. Tested against an edition that no longer matches your specification or current regulatory acceptance.
• Values, not verdicts, missing. Every clause says “pass” with no measured values, ambient conditions or test circuits recorded.
• Report date after your enquiry date is fine — but a report with no date at all is not. Traceability matters for asset records and future audits.

Frequently asked questions

What is the difference between a type test and a routine test on switchgear?

A type test validates a design against a standard and is performed once per design and rating envelope, often destructively. A routine test is performed on every individual unit before shipment and only confirms that the unit was assembled and wired correctly. Only a type test proves that the design can withstand dielectric, thermal and short-circuit stresses.

Which standard applies to a medium-voltage switchgear type-test report?

For factory-assembled metal-enclosed switchgear rated above 1 kV and up to 52 kV, the reference standard is IEC 62271-200 (national equivalents include GB/T 3906). The switching device inside is separately covered by IEC 62271-100 for circuit breakers. Always confirm the edition year cited in the report matches the edition your specification requires.

Can a supplier’s type test cover a higher rating than the one tested?

Not automatically. A report is valid for the ratings actually tested. Higher ratings require either a new test or a formal extension report issued by the testing laboratory based on defined similarity rules — covering aspects such as identical enclosure geometry, busbar arrangement and insulating materials. Without that extension document, a higher rating is unproven.

How long is a type-test report valid?

The report itself does not expire as long as the design, ratings, materials and critical component suppliers remain unchanged. However, the edition of the standard may be superseded, and many utilities and EPC contractors require reports issued within a certain number of years or against the current edition. Reputable manufacturers re-test or issue updated reports when a new edition is published.

What does an IAC classification such as “A FLR 25 kA 1 s” mean?

It means the assembly withstood an internally initiated arc fault of 25 kA for 1 second while protecting personnel on the accessible sides declared: front (F), lateral (L) and rear (R). The leading “A” indicates the type of accessibility. Pay attention to which compartments were tested and whether pressure-relief ducting was installed, as these conditions limit how the classification transfers to your installation.

Should I ask for the oscillograms and photographs?

Yes. Oscillograms are the raw evidence that the test was actually performed at the stated current and duration, and photographs of the sample before and after testing confirm the object tested. Together they are the fastest way to distinguish a genuine full type test from a summary document.

Does a withdrawable truck need separate type testing from the cubicle?

The assembly and the switching device are tested to their respective standards, and the combination must be consistent. The truck-mounted circuit breaker needs its own IEC 62271-100 type test at the relevant voltage and breaking capacity, and the mechanical interlocks between truck and cubicle must be verified within the assembly test. Check that the breaker series in the report is the same series quoted to you.

What if the report language is not English?

Ask for an English translation issued by the testing laboratory or a certified translation covering the identity block, test clauses and conclusions. For international tenders, the summary page plus the standard and rating tables are usually sufficient for pre-qualification, with the full translation supplied at contract stage.

A practical self-audit you can run in five minutes

Before a report goes into your tender file, run this quick check. If you answer “no” to any of the first four, stop and request clarification.

Заключение

Reading a switchgear type-test report is a skill that pays for itself on the first project where it catches a mismatch. Start with the identity block, confirm the rating envelope covers your order, then work through dielectric, thermal, short-circuit, internal arc and mechanical evidence in that order. Insist on measured values rather than bare “pass” statements, and treat any missing duration, missing compartment detail or missing laboratory accreditation as a question to be answered — not a formality to be waived.

Well-documented switchgear is not an accident of marketing; it is the result of a design that was actually built to a standard and actually tested. Asking for the report is the fastest way to find out which one you are being offered.

Related resources

• Switchboard vs Switchgear: What Is the Difference? — clarifies the terminology before you specify.
• Internal Arc Fault Suppression Technology of Medium Voltage Switchgear — the engineering behind IAC classifications.
• Welding Process Standards for Anti-Corrosion Switchgear Cabinet Frames — how enclosure build quality affects long-term compliance.
• Maintenance and Servicing of Outdoor High Voltage Vacuum Circuit Breakers — keeping tested performance intact in service.