A significant portion of CE consultancy requests start with this question: "Do we need to send our product to a laboratory, or can we proceed with our existing documentation?" Although this question seems simple at first glance, it actually requires a multi-layered assessment depending on the product's risk profile, design, and the targeted conformity assessment route. In this article we cover in which cases laboratory testing is mandatory in the CE process, when calculations and documentation may be considered sufficient, the most common test types, and how test planning should be carried out.
Factors That Determine the Need for Testing
Whether a product requires laboratory testing does not depend on a single rule, but on the combined assessment of several factors. The first factor is the nature of the directive or regulation applied to the product; because some directives (such as RED) contain directly measurable physical performance criteria, proving conformity in practice without testing is nearly impossible. The second factor is the product's risk class; for a low-risk, simply designed product, engineering calculations and material certificates may be considered sufficient evidence, while for a high-risk or complex product, testing becomes unavoidable. The third factor is the chosen conformity assessment module: under the self-declaration model, the manufacturer can determine the test scope according to its own risk assessment, while for products requiring notified body involvement, the test scope is largely determined by the procedures of the relevant module.
Standard-Based Design and the Need for Testing
If a product is designed in full compliance with the relevant harmonized standard and that standard clearly defines the test methods, testing is generally carried out using the method prescribed by the standard, and the result directly provides a "presumption of conformity." However, if the manufacturer chooses a design that deviates from the standard (for example, using a different material or a different protection class), a non-standard engineering justification and generally additional testing are expected to demonstrate an equivalent level of safety. For a general framework on the role of standards in the CE process, see our article Which Directives Apply to My Product?.
Which Test Types Are Required in Which Cases?
LVD (low voltage) tests verify electrical safety against electric shock, overheating and fire risk for electrical products within a certain voltage range. RED (radio equipment) tests cover both radio frequency performance and electrical safety elements together, for devices with wireless communication capability. Mechanical safety tests measure physical parameters such as accessible surface temperatures, moving part distances, stability, noise and vibration for machinery and mechanical equipment. In addition to these, IP (dust/water ingress) and IK (impact resistance) tests may also be required depending on the product's environment of use.
Cases Requiring Notified Body Testing
For some high-risk product categories (for example, machinery listed in specific annexes of the Machinery Directive, or higher categories of personal protective equipment), tests must be carried out by an independent notified body, or the notified body must at least oversee the test process. In such cases, the manufacturer may conduct preliminary tests in its own laboratory, but for final proof of conformity, the notified body must be involved in the process. You can find detailed information on how this distinction is made in our article What Is a Notified Body?.
When Is Calculation and Analysis Sufficient Instead of Testing?
Not every essential requirement necessarily needs to be proven with a physical test. Some parameters, such as structural strength, can also be proven with validated engineering calculation methods (for example, finite element analysis) or with certified data from previously tested similar components. This approach is used especially for low-volume, custom-designed products to optimize test costs; however, the calculation method used must be consistent with the relevant standard and documented with justification in the technical file.
The Role of Tests in the Technical File
A test report is not, on its own, a "certificate"; it is a piece of evidence that completes the integrity of the technical file. In audits and notified body reviews, the mere existence of a test report is not considered sufficient; whether the tested sample is identical to the mass-produced product, whether the applied test method complies with the declared standard, and whether the test results meet the limits prescribed by the standard are also separately assessed. For this reason, when attaching a test report to the technical file, clearly stating which product revision the report belongs to and which standard clauses it covers prevents inconsistency questions later on.
Strategies for Optimizing Test Costs
Test costs are one of the most tangibly felt line items in the CE process, especially for SME-scale manufacturers. There are several ways to keep these costs at a reasonable level: planning tests at the prototype stage to prevent costly revisions after mass production; using a product family approach to test a single representative model for minor variations that do not affect safety performance; and combining different test types (LVD, mechanical) at the same laboratory and in the same visit as much as possible to reduce logistics and sample preparation costs. However, none of these optimization efforts should mean skipping a required test; the goal is to structure the process efficiently, not to narrow its scope.
Changes That Require Retesting
Not every change made to a product requires retesting; however, changes that can affect safety performance, electromagnetic behavior or mechanical strength (for example, revising an electronic board, changing the power supply, or changing the housing material or dimensions) generally require the relevant tests to be at least partially repeated. The manufacturer systematically making this assessment at every design revision and documenting its justification in the technical file both preserves consistency and ensures readiness for the question "why wasn't retesting done" during a possible audit.
Points to Consider When Choosing a Laboratory
Choosing the right laboratory affects the speed of the process as much as the validity of the test. It must be ensured that the laboratory's accreditation scope is current for the product group being tested and the relevant standard; a test carried out outside the accreditation scope may not be accepted as valid evidence in audits and notified body reviews, even if it technically produces a correct result. In addition, the laboratory's appointment and reporting turnaround times directly affect the project schedule, especially for products with a set market entry date. If multiple test types are required across long supply chains, consultancy support that plans tests in a coordinated manner and, when necessary, organizes sample transfer between different laboratories can shorten the total duration of the process.
What Happens If Test Results Are Non-Conforming?
A test result failing to meet the limits prescribed by the standard does not mean the end of the process, but a return to the design review cycle. In this case, the root cause of the non-conformity (such as material selection, circuit design, or mechanical tolerance) is generally identified first, a targeted revision is made to the design, and the relevant test is repeated only for the affected parameter; repeating the entire test from scratch is not always necessary. Experiencing this cycle as early as possible, i.e. at the prototype stage, protects against a much more costly revision risk that could arise for a product that has already moved into mass production.
Test planning cannot really be fully grasped without understanding how the CE certification process proceeds as a whole. To see at which step of the process tests should be planned and how they relate to other steps, see our article The CE Certification Process, Step by Step.
Relevant Directives and Standards
The main legislation forming the basis of test requirements is as follows: Low Voltage Directive (LVD) 2014/35/EU for electrical product safety, Radio Equipment Directive (RED) 2014/53/EU for wireless communication devices, and Machinery Directive 2006/42/EC for mechanical equipment (gradually being transferred to Machinery Regulation (EU) 2023/1230). Test methods are set out in the harmonized EN standards underlying these directives (for example, EN 62368-1 or product-specific EN 60335 series for electrical safety). Which laboratory can carry out the tests depends on the laboratory's accreditation scope; accreditation is an independent quality assurance mechanism that confirms the reliability of test results.
| Test Type | Relevant Directive | When Required |
|---|---|---|
| Electrical safety (LVD) | 2014/35/EU | Electrical products within a certain voltage range |
| Radio frequency performance | 2014/53/EU | Devices with wireless communication capability |
| Mechanical safety | 2006/42/EC | Machinery with moving parts, sharp surfaces or stability risk |
| IP / IK protection class | Product-specific type C standards | Products exposed to outdoor environments or impact risk |
Step-by-Step Process
- Identify the directives and regulations applicable to the product and determine which essential requirements require testing.
- Review the relevant harmonized standards to clarify whether each requirement can be proven through testing or calculation.
- Determine whether the product requires self-declaration or notified body involvement.
- Choose a laboratory with the appropriate accreditation scope.
- Carry out preliminary testing at the prototype stage to identify potential non-conformities before mass production.
- Prepare test samples and the test plan according to the conditions prescribed by the relevant standard.
- Record the test results in the technical file and check their consistency with the declared standards.
- Assess whether retesting is required whenever there is a change in the product design or the components used.
Most Common Mistakes
- Realizing the need for testing only after moving into mass production and being forced into costly design revisions.
- Obtaining a report from a laboratory whose accreditation scope does not match the product.
- Continuing to use a test report as if valid after the product design has changed.
- Relying only on internal tests for a product requiring notified body involvement.
- Not providing additional testing or evidence of equivalence for a design choice that deviates from the standard.
- Failing to cross-check test reports against the list of declared standards in the technical file.
- Not reflecting differences between models in the same product family in the test scope.
Frequently Asked Questions
Is laboratory testing mandatory for every product?
No. For some products, design calculations, material certificates and a harmonized-standard compliance analysis may be sufficient; the need for testing varies with the product's risk level and complexity.
What do mechanical safety tests measure?
Mechanical safety tests can cover the sharpness/temperature of accessible surfaces, access distances to moving parts, stability and durability performance, and noise and vibration levels.
Can a test report be obtained from a laboratory abroad?
Yes, the validity of a test report depends on the laboratory's accreditation scope and the standard it applies; a report from an accredited laboratory can be used in the technical file regardless of country.
Can a manufacturer complete the CE process with its own internal tests?
Under the self-declaration model, some tests can be carried out in the manufacturer's own laboratory with appropriate equipment and methodology; however, for products requiring notified body involvement, tests must be carried out at an independent, accredited laboratory.
Does a test report have a validity period?
There is no fixed expiration date for the test report itself; however, if the product design, the components used, or the relevant standard changes, the test report loses its validity and retesting may be required.
Is RED testing required only for wireless devices?
Yes, tests under the Radio Equipment Directive are required for devices with wireless communication capability (Wi-Fi, Bluetooth, RF module, etc.); products without wireless features are exempt from this test.
Who pays for the cost of testing?
The cost of testing is borne by the manufacturer; the cost varies depending on the type of test, product complexity and the laboratory chosen. See our article What Determines the Cost of CE Certification? for general cost factors.
Does testing at the prototype stage provide an advantage?
Yes, carrying out preliminary tests at the prototype stage allows potential non-conformities to be identified and corrected before mass production begins, and prevents costly design changes later on.
Must every model in the same product family be tested separately?
If there are minor differences between models that do not affect safety performance, testing can usually be carried out on a representative model and the results applied across the family; however, the justification for this approach must be clearly documented in the technical file.
Is it possible to obtain CE marking through calculation alone, without testing?
For some low-risk product groups and certain essential requirements, engineering calculations and design analyses may be considered sufficient evidence; but which requirements this approach applies to must be assessed on a product-specific basis.
Why does accreditation matter when choosing a laboratory?
A test carried out outside the accreditation scope may not be accepted as valid evidence in audits and notified body reviews, even if it technically produces a correct result; for this reason it must be ensured that the laboratory holds current accreditation for your product group and the relevant standard.
How can the process be shortened when multiple test types are required?
Planning different test types (LVD, mechanical) at the same laboratory as much as possible, on a coordinated schedule, can reduce the total duration by cutting down on repeated sample preparation and logistics.
Conclusion
The need for testing in the CE process is not a matter of a single general rule, but one that must be assessed together with the product's directive scope, risk class and design choices. Planning testing early, at the prototype stage, both ensures early detection of design errors and prevents costly revisions that could arise after mass production. The right test strategy directly affects both the speed and the reliability of the CE process. Viewing test planning not as a cost item but as a verification tool that shows the product's actual performance and market readiness means safer products and less audit and complaint risk in the long run. This perspective forms a valuable reference point that guides design decisions correctly at an early stage, especially for R&D teams developing new products.
If you're not sure about your product's testing needs, let's assess it together. For more information, see our CE consultancy service.
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