Test & measurement
Safety critical components must be approved to relevant component standards (if any). These include testing that cannot be conducted (or in some cases only partially) in the end product assessment, for example endurance and loading of switches.
They must also comply with any specific requirements in the end product standard, and must be used within its ratings (voltage, current or power, rated max. temperature etc.). In addition to an accredited test report, components approved to an IEC standard must also have a CB Certificate if that standard is included in the CB scheme. Other international or national approvals may sometimes be accepted in lieu of CB Certification and reports, provided that the standard applied is technically equivalent to the IEC component standard.
One example is to use standards with different prefixes where the number that follows is identical, as in this example:
“If a required standard for a safeguard component is IEC 61058-1 (for switches) then
Instrumentation Monthly June 2025
the Cenelec standard EN 61058-1 may be used instead, as the Cenelec version is technically equivalent to the IEC standard, including test and compliance criteria. Note that the edition or date of publication may not be the same as the IEC standard, so this must be checked to ensure that it is the equivalent version.”
Some components or modules might be previously approved to an end-product standard instead of a component standard. This is usually the case where there is no appropriate component standard, or where the ‘component’ is an end product in its own right e.g. motherboards, power supplies, pumps, battery packs. In this case, the approval must also be acceptable in the end-product standard being used and the same ‘rules’ apply for acceptance as for any other component (as above). Some components in this section may also need additional verification to ensure that tests and compliance criteria are sufficient to meet the requirements for the end product. It is essential that, in addition to certification, the full test reports are also available.
Alternate national or regional standards may be required for some countries or regions. Some common examples are North America, the EU, UK, Japan, Australia/New Zealand. It is also worth noting that a manufacturer’s Declaration of Conformity or a self-issued Certificate of Conformance is not acceptable in lieu of third- party accredited testing and certification. In some cases, an end product standard may allow for some components to be assessed in the end-use application. This usually requires additional in-application testing but some components often cannot be tested solely in application, e.g. fuses. Electric shock, fire and other hazards related to the use of electronic products are the cause of thousands of injuries and even deaths around the world each year, whether because of poor design, inadequate maintenance, or unintended use. Evaluating and testing a product, and its safety critical components, is therefore essential to mitigate potential risks and ensure end-user safety.
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