Why Do Products Fail Conformity Tests? And How Can You Avoid Retesting?

A product’s failure to pass a compliance test is one of the most costly challenges in the market entry process. The consequences of failure may extend beyond retesting fees to include design modifications, production delays, remanufacturing of samples, label changes, shipment postponements, or missing the product launch date.

However, a non-conformity does not always mean that the product is of poor quality overall. The product may perform well, but it may fail to meet a specific requirement in the standard, have been tested using an inappropriate test method, have technical specifications that do not match the sample, or contain a component used in production that differs from the one that was evaluated.

Therefore, compliance should be treated as a project that begins with the design phase, rather than a test conducted at the end of production.

What does it mean to fail a compliance test?

A failure occurs when a sample does not meet one or more of the requirements specified in the standard or technical regulation.

The discrepancy may be related to:

• Electrical Safety.
• Temperatures.
• Insulation resistance.
• Impact protection.
• Electromagnetic Compatibility.
• Mechanical strength.
• Ignition.
• Chemicals.
• Energy efficiency.
• Water consumption.
• Wireless communication.
• Warnings and labels.
• Instructions for Use.
• Tracking and Model Identification.

A certified laboratory does not determine a product's compliance based on general impressions; rather, it performs specific test methods and compares the results to documented limits and requirements.

The ISO/IEC 17025 standard sets out requirements for the competence, impartiality, and consistency of laboratory operations, as well as their ability to produce valid and reliable results.

Reason 1: Choosing the wrong criterion

One of the most common reasons is starting the test before determining the correct criterion.

This may occur when the factory relies on:

• Brand Name.
• Experience with a similar product.
• A standard used in a different market.
• An older version of the standard.
• Inaccurate product classification.
• The assumption that a secondary function does not affect the requirements.

A product may be subject to more than one standard, especially if it combines electrical, wireless, and mechanical functions.

How can you avoid this problem?

A regulatory review must be conducted before requesting a quote from the laboratory, and the following must be determined:

• Target market.
• Applicable regulations.
• Standards and their versions.
• Additional tests.
• National Differences.
• Conformity Assessment Method.

Reason 2: Ignoring National Differences

The test report may be based on an international standard, but the target market may apply national variations or additional requirements.

The IECEE system specifies that a test report may require additional testing if it does not cover the declared national differences for the country in which it will be used.

National differences may relate to:

• Voltage and frequency.
• The plug and power cord.
• Ambient temperatures.
• Warnings.
• Language.
• Security Components.
• Local conditions of use.
• Energy Efficiency Requirements.

How can you avoid this problem?

Identify the target countries before the test, and ask the lab to clarify which national differences the report will cover.

Reason 3: The sample is not representative of the final product

The test sample must be representative of the product to be manufactured and shipped.

The problem occurs when:

• A prototype is tested, and then the components are modified.
• The power adapter is replaced with another one.
• The battery is being replaced.
• The circuit board is being modified.
• The plastic material changes.
• A wireless component is added.
• The factory or production line changes.
• The ventilation openings or the dimensions of the structure vary.

In certification programs, the continued validity of technical evidence is contingent upon the product continuing to conform to the condition under which it was evaluated. The IECEE clarifies that a CB certificate remains valid as long as the product continues to conform to its original certificate.

How can you avoid this problem?

Implement a change management system that prevents the replacement of any critical component without reviewing its impact on compliance.

Reason 4: Use of unsuitable ingredients

A product may fail because of a small component, even though the overall design appears sound.

Critical components include:

• Fuses.
• Transformers.
• Batteries.
• Keys.
• Connectors.
• Wires.
• Insulation materials.
• Flame-resistant materials.
• Protection Circuits.
• Engines.
• Wireless communication units.

The characteristics of these components must be consistent with the operating conditions and limits specified in the product design.

How can you avoid this problem?

Create a list of critical components, gather their certificates, reports, and specifications, and verify that the actual model numbers match those in the documentation.

Reason 5: Rising temperatures

Temperature testing is one of the critical aspects of electrical products.

The temperature may rise due to:

• Poor ventilation.
• Keep hot components away from plastic materials.
• Use of an unsuitable adapter.
• Loading the product beyond its design capacity.
• Inefficient heat dissipation design.
• Test conditions differ from those in internal experiments.

How can you avoid this problem?

Conduct preliminary tests under maximum operating conditions, not just under average usage conditions. The worst-case scenario must be evaluated, including full load, voltage, and ambient temperature.

Reason 6: Inadequate electrical insulation and protection

The product may fail due to insufficient spacing between circuits, poor insulation, or easy access to hazardous parts.

Potential problems include:

• Insufficient ground clearance.
• Loose wiring.
• Poor grounding.
• Risk of coming into contact with an electrical component.
• The insulation cannot withstand the required voltage.
• Insufficient protection against liquids or dust.
• Use of an inappropriate insulation material.

How can you avoid this problem?

The design of the circuit board, the structure, and the components must be reviewed in accordance with the provisions of the standard before the final mold is manufactured or mass production begins.

Reason 7: Electromagnetic Compatibility

The device may operate normally, but it may generate electromagnetic emissions that exceed the limits, or it may be affected by external interference.

The problem may be caused by:

• Inappropriate layout of the electronic board.
• Unshielded cables.
• Poor grounding.
• The Absence of Female Candidates.
• Inappropriate cover design.
• The supplier for one of the ingredients has changed.
• The cable used during the test was different.

How can you avoid this problem?

It is preferable to conduct preliminary electromagnetic compatibility (EMC) tests during the development phase, because addressing the issue after the design is complete may require extensive modifications.

Reason 8: Incomplete technical file

The sample may pass the tests, but the project may be halted due to missing or inconsistent documentation.

Shortcomings may include:

• Lack of plans.
• Missing component specifications.
• No risk assessment.
• Discrepancies in the model across documents.
• No clear images.
• Missing ingredient reports.
• Incomplete instructions for use.
• Invalid declaration of conformity.
• The actual factory was not specified.

International conformity assessment systems emphasize the importance of the technical file; under the CE system, the manufacturer is responsible for conducting the conformity assessment, preparing the technical file, issuing the declaration of conformity, and affixing the required marking.

How can you avoid this problem?

Prepare the technical file in parallel with product development; don't wait until testing is complete to start gathering the documentation.

Reason 9: Errors in Labels and Warnings

Labels are sometimes viewed as a marketing tool, but they are part of the compliance requirements.

The problem might be:

• Lack of effort or ability.
• Error in the model name.
• Failure to identify the manufacturer or supplier.
• Use of an unauthorized trademark.
• Incomplete warning.
• The font size is unclear.
• The sticker material is not durable enough for regular use.
• The label differs from the report.
• The requested language is not available.
• Batch number or serial number is missing.

Responsibilities related to launching products in multiple international markets include providing labels, instructions, warnings, and information that help identify the product, trace its origin, and ensure its safe use.

How can you avoid this problem?

Please send the poster design and usage instructions for review before printing and mass production.

Reason 10: Choosing an unsuitable laboratory

The laboratory may be accredited in general, but the scope of its accreditation does not cover the required standard or test.

Problems such as the following may arise:

• The report was not accepted by the certifying authority.
• The need for retesting.
• Failure to address national disparities.
• Lack of specific testing equipment.
• Lack of experience in this product category.
• The report format does not conform to the required template.

How can you avoid this problem?

Verify the laboratory’s scope of accreditation, the certification body’s acceptance of the laboratory, its experience with the product, and its ability to perform all required tests.

Reason 11: Poor Project Management

The cause of the delay may not be purely technical, but rather poor coordination between the manufacturer, the importer, the laboratory, and the certifying authority.

The issues include:

• Delayed responses.
• Submit different versions of the documents.
• A clear lack of accountability.
• Failure to track comments.
• Failure to document changes.
• Send samples without their accessories.
• Failure to prioritize the tests.
• Completion of some reports during the project.

How can you avoid this problem?

The project must have:

• Key official.
• List of Standardized Documents.
• A notebook for notes.
• Schedule.
• A version numbering system.
• Mechanism for Adopting Amendments.
• Regular updates for all parties.

What is a pre-conformity review?

A pre-conformity review is an evaluation of the product and documentation prior to formal testing.

These typically include:

• Design Review.
• Defining the criteria.
• Component Analysis.
• Check the labels.
• Review the instructions for use.
• Gap Analysis.
• Preliminary tests as needed.
• Prepare a test plan.

This review does not guarantee success, but it minimizes surprises and helps identify problems when the cost of fixing them is lower.

What should you do if you fail an exam?

If a discrepancy is found, avoid making arbitrary changes to the product.

Start with the following steps:

Understand the "failure" clause

Please provide a clear description of the test, the result, and the required threshold.

Identify the root cause

Distinguish between the symptom and the actual cause. For example, a rise in temperature could be caused by ventilation, the transformer, the load, or the material.

Assess the impact of the amendment

A fix may resolve one issue but affect another test.

Document the new release

The diagrams, bill of materials, images, and interior model must be updated.

Agreed on the scope of retesting

It may not be necessary to repeat all tests if the laboratory and the certifying authority agree on a specific scope for verifying the modification.

Summary

Failures in conformance testing are rarely caused by a single factor; rather, they result from an accumulation of small decisions that began during the design phase, component selection, or documentation preparation.

The best way to minimize the likelihood of failure is to integrate compliance into the product development process from the very beginning—by defining standards, reviewing the design, validating components, preparing the technical documentation, selecting the appropriate laboratory, and managing changes in an organized manner.

CAP helps companies conduct pre-conformity reviews, analyze the causes of failure, coordinate with laboratories, prepare corrective action plans, and follow up on retesting and certification procedures until the project is completed.