What Test Reports Should You Ask an SPD Manufacturer for Before Bulk Ordering?

• Why Generic Certificates Are Not Enough for Bulk SPD Procurement
• The Five-Step Audit: Model, Standard, Test, Report, and Parameters
• 8/20 µs vs. 10/350 µs: Why the Waveform Matters
• Case Study of Report‑Document Consistency 
• A Practical Pre-Order Checklist
• Conclusion
• FAQ

TECHNICAL GUIDE | ELECTRICAL SAFETY

When buying SPDs in bulk, buyers may rely on compliance certificates to verify product quality. However, certificates show general compliance and do not prove that a specific SPD passed all relevant tests or meets its datasheet performance. Poor verification can lead to equipment damage, rework, and delays.

Reliable SPD manufacturer quality control should include clear, traceable test documentation. Buyers should check the exact model, standard and edition, test items, laboratory credentials, and key parameters. They should also distinguish 8/20 µs and 10/350 µs surge waveforms and ensure they match the appropriate SPD type.

Why Generic Certificates Are Not Enough for Bulk SPD Procurement

Certificates of conformity and declarations are useful for supplier qualification, but they should not replace a complete SPD test report. A certificate generally confirms that a product or product family meets specified requirements, while a test report provides the tested model, test conditions, applicable standard, and measured results.

For products with multiple models or OEM versions, buyers should confirm that the report matches the exact model and configuration being ordered. The applicable standard edition should also be checked to ensure it meets current project requirements.

In simple terms, a certificate confirms compliance at a general level, while a detailed test report provides stronger evidence for technical verification.

The Five-Step Audit: Model, Standard, Test, Report, and Parameters

A practical SPD test report review can be organized into five steps: verify the exact model, confirm the applicable standard, review the required tests, check report traceability, and compare the test results with the product specifications.

Check the Exact Model Number

Start by checking whether the test report identifies the exact SPD model you intend to purchase. The complete model designation should be considered, including voltage ratings, pole configuration, and any suffixes that identify a specific variant.

For example, if the purchase order specifies CSMS-B40/AC385-3P+N, the test documentation should clearly identify that configuration rather than referring only to the broader CSMS-B40 series.

OEM orders require additional attention. Changes to the enclosure, terminals, internal components, or electrical configuration may affect the scope of an existing test report. Before placing a large OEM order, ask the manufacturer to confirm in writing whether the customized version remains covered by the available certification and test documentation.

You should also check whether the report covers all relevant protection modes. For multi-pole SPDs, this may include L-N, L-PE, and N-PE paths, depending on the product design and application.

Confirm the Applicable Standard and Edition

The next step is to verify the standards referenced in the report. For low-voltage AC power SPDs, buyers commonly encounter IEC 61643-01 and IEC 61643-11, while signal and telecommunications SPDs are covered by the relevant requirements of IEC 61643-21.

Do not look only at the standard number. Check the edition and make sure it is appropriate for your project requirements. If the report references an older edition, ask the manufacturer or testing laboratory whether the report remains applicable to the specific certification or project specification you are working with.

This is especially important when a project specification explicitly requires compliance with a particular edition. An older test report can provide valuable technical evidence, but it should not automatically be presented as proof of compliance with requirements that were introduced or revised later.

Review the Test Items Relevant to Your SPD

After confirming the model and standard, review the actual test sections in the report. A summary page showing “PASS” is useful, but it does not provide the same level of information as the detailed test results.

Understanding the applicable surge protector testing requirements is important because Type 1, Type 2, and Type 3 SPDs are evaluated under different surge conditions.

For Type 1 SPDs, typical areas of review include impulse current testing, voltage protection level (Up), follow-current behavior where applicable, short-circuit performance, thermal protection, dielectric strength, and insulation-related tests.

For Type 2 SPDs, pay particular attention to 8/20 µs discharge-current testing, including nominal discharge current (In) and maximum discharge current (Imax), as well as voltage protection level, operating-duty tests, temporary overvoltage behavior, and thermal disconnector performance where applicable.

Type 3 SPDs are generally evaluated using combination-wave testing, involving a 1.2/50 µs voltage impulse and an 8/20 µs current impulse. DC and PV applications may involve additional requirements related to DC voltage stress and arc behavior. Signal-line SPDs also require consideration of transmission characteristics because surge protection should not unnecessarily compromise communication performance.

If a required test is listed as “not performed,” or if an important test section is missing from the report, ask the manufacturer to explain why before approving the product for a large-volume order.

Check the Report Number and Laboratory Credentials

A formal third-party test report should normally include a unique report number and sufficient information to identify the testing laboratory. Record the report number and check the laboratory's credentials, including relevant accreditation such as ISO/IEC 17025 where applicable.

Be cautious with documents that contain only selected pages or screenshots. If the laboratory name, report number, test conditions, or detailed results have been removed, it becomes much harder to verify the document independently.

For major projects, it is good practice to request the complete SPD test report rather than relying on a short certificate, marketing brochure, or selected test-result page. This gives your engineering or quality team enough information to review the test conditions and determine whether they match the intended application.

Compare the Test Results with the Datasheet

The final step is to compare the laboratory results with the manufacturer's datasheet and the technical requirements stated in your purchase order.

Key parameters may include maximum continuous operating voltage (Uc), voltage protection level (Up), nominal discharge current (In), maximum discharge current (Imax), impulse current (Iimp), short-circuit rating, and SPD classification.

The numbers should make sense across all documents. If the datasheet lists an Imax value of 80 kA but the test report does not show testing at that level, ask the supplier for clarification. There may be a legitimate reason for the difference, such as different test conditions or a specification based on another product configuration, but the discrepancy should be explained before the order is approved.

This cross-check is one of the simplest ways to identify inconsistencies between product marketing information and laboratory evidence.

8/20 µs vs. 10/350 µs: Why the Waveform Matters

One of the most common sources of confusion when reviewing SPD specifications is the difference between 8/20 µs and 10/350 µs current impulses. These waveforms are not interchangeable, even when the peak current is expressed using the same kA value.

The 10/350 µs waveform is associated with lightning-current testing for Type 1 SPDs and represents a much higher energy impulse than an 8/20 µs waveform at the same peak current. The key rating for this type of test is generally Iimp. Type 1 SPDs are typically installed at the service entrance or other locations where a portion of lightning current may enter the electrical installation.

The 8/20 µs waveform is commonly used to evaluate Type 2 SPDs. It is associated with induced lightning surges and switching transients, and the relevant ratings generally include In and Imax. Type 2 SPDs are commonly installed downstream of the main service entrance to provide additional protection for distribution circuits.

Type 3 SPDs are normally evaluated using a combination wave, which combines a 1.2/50 µs voltage impulse with an 8/20 µs current impulse. These devices are typically installed close to sensitive equipment as part of a coordinated protection system.Correct interpretation of surge protector testing requires buyers to consider the waveform, peak current, energy, test circuit, and SPD classification together.

The important point is that a higher kA number does not necessarily mean a higher level of protection. The waveform, test circuit, energy, SPD classification, and test conditions all matter. An SPD that withstands a certain current under an 8/20 µs test cannot automatically be assumed to withstand the same peak current under a 10/350 µs test.

When reviewing a report, always check the waveform together with the SPD type and intended installation position:

• Type 1 SPD → 10/350 µs impulse current → Iimp → service entrance
• Type 2 SPD → 8/20 µs impulse current → In / Imax → distribution panels
• Type 3 SPD → combination wave → point-of-use protection

If the test data and product classification do not appear to match, ask the manufacturer for clarification before relying on the report for procurement approval.

Case Study of Report‑Document Consistency

For an overseas bulk procurement project of Type 2 SPDs for photovoltaic systems, buyers planned to order a 3P+N variant rated AC385 V. The supplier first provided Cresin’s public certificate page, including CE, ISO 9001, ISO 14001, and ISO 45001 certificates. However, these documents were general compliance and management certificates rather than model-specific SPD test reports.

The supplier later submitted a third-party test report for a 4P model from the same product family and claimed it could support the 3P+N order. During document review, inspectors identified two issues: the tested configuration did not match the ordered 3P+N version, and the report referenced an older edition of IEC 61643-11. Since the project required specific model and standard compliance, buyers requested a test report covering the exact 3P+N configuration before confirming the order.

A Practical Pre-Order Checklist

Before confirming a large SPD order, use the following workflow:

1. Ask the manufacturer for test documentation covering the exact model listed on your purchase order or bill of materials.
2. Check the applicable IEC standard and edition against your project requirements.
3. Review the relevant test items instead of relying only on a summary “PASS” statement.
4. Record the test report number and verify the testing laboratory and accreditation information.
5. Compare Uc, Up, In, Imax, Iimp, short-circuit ratings, and SPD classification across the report, datasheet, and purchase-order specification.
6. Confirm that the waveform used in the test corresponds to the SPD type and intended application.
7. For OEM or customized products, obtain written confirmation that the final configuration remains within the scope of the available test documentation.
8. Keep complete copies of the approved reports for project records, inspections, and future maintenance.

For bulk procurement, documentation review should be considered together with SPD manufacturer quality control. Buyers can evaluate whether the supplier has appropriate testing procedures, production controls, sample inspection, and traceability systems to maintain consistency between tested products and mass-produced units.

For large projects, document review should also be supported by sample evaluation where practical. Laboratory reports describe the performance of tested samples under controlled conditions. Evaluating production samples can provide an additional level of confidence that the products supplied in bulk are consistent with the documented design.

Conclusion

Manufacturer-operated in-house laboratories also deliver reliable validation; CRESIN’s dedicated Testing Laboratory is detailed on its website, outlining its complete SPD performance-verification workflows.These testing capabilities can also form an important part of SPD manufacturer quality control, helping manufacturers verify product performance before shipment.

Shandong Cresin Electric Co., Ltd. maintains a standardized production workshop. You can learn more about our production capacity on our Factory page. We also offer flexible custom SPD solutions for OEM customers. Visit our OEM page to explore our custom manufacturing capabilities.

A certificate is useful, but it should not be the only document you review before placing a large SPD order. A more reliable procurement process combines certification with detailed test-report verification.

By checking the exact model number, applicable standard and edition, test coverage, report traceability, and consistency of key parameters, procurement and engineering teams can identify documentation gaps before they become costly field problems.

It is equally important to interpret surge-test waveforms correctly. The 8/20 µs and 10/350 µs waveforms represent different test conditions and are used in different SPD applications. Comparing their kA ratings directly can lead to misleading conclusions about product capability.

Before approving your next bulk shipment, ask your SPD manufacturer for complete test documentation for the exact model you intend to purchase. Clear, traceable test reports give buyers a stronger technical basis for evaluating product performance, supplier quality, and long-term project reliability.

If you are evaluating an SPD supplier for a bulk order, OEM project, solar PV system, industrial application, or electrical distribution project, Shandong Cresin Electric Co., Ltd. can provide product specifications, technical documentation, test reports, and customized surge protection solutions. Our technical team can also help you review the appropriate SPD type, protection parameters, and documentation for your application. Contact Us to discuss your project requirements and find a suitable surge protection solution.

FAQ

What test reports should I request from an SPD manufacturer?

You should request a complete test report for the exact SPD model you plan to purchase. The report should identify the model number, applicable IEC standard and edition, relevant test items, test conditions, measured results, report number, and testing laboratory. A generic certificate alone is usually not enough for technical due diligence on a bulk order.

Is a certificate enough to verify SPD quality?

Not necessarily. A certificate can confirm that a product or product family has been assessed against certain requirements, but it may not show the detailed test conditions or measured results for your specific model. For large projects, a complete laboratory test report provides more useful technical evidence.

What is the difference between 8/20 µs and 10/350 µs testing?

The two waveforms represent different surge conditions and energy levels. The 8/20 µs waveform is commonly associated with Type 2 SPD testing and ratings such as In and Imax, while the 10/350 µs waveform is associated with Type 1 SPD testing and the Iimp rating. Their kA values should not be compared directly without considering the waveform and test conditions.

Should I request a test report for an OEM SPD?

Yes. For an OEM or customized SPD, confirm that the final configuration is covered by the manufacturer's existing test documentation. Changes to electrical components, terminals, enclosure design, or other critical features may affect the scope of the original testing.

What parameters should I compare between the test report and datasheet?

At minimum, compare Uc, Up, In, Imax, Iimp where applicable, short-circuit ratings, SPD type, rated voltage, and pole configuration. Any significant discrepancy should be clarified with the manufacturer before the bulk order is approved.