What is a Critical Component – And Who in Your Organisation Needs to Know?
Authors:
Erica Sundgren, QA/RA Consultant MedTech, Orderly People
Alfred Samuelsson, Co-founder and CEO, Certainli
Why critical components matter
If you work with hardware development, you already manage risk. You run functional verification and testing of your design. You check the component datasheets to ensure they meet your technical requirements, and perform EMC pre-compliance testing before taking a product to market.
But one area still creates friction in many projects: identifying and controlling critical components early enough – and documenting them correctly.
A critical component list is not administrative overhead. It is a core part of your product's Technical File during external safety testing and certification. If it's incomplete, unclear, or outdated, it can slow down approvals, trigger audit findings, or force partial re-testing.
This applies across regulated electronic products – industrial systems, IT/AV equipment under IEC 62368-1, and medical devices under IEC 60601-1. It is a key consideration for any product falling under the Low Voltage Directive (LVD) or the Radio Equipment Directive (RED).
Let's define what we actually mean.
What is a critical component?
In the context of electrical safety testing
A critical component is any part, material, subassembly, system, or accessory that has a direct impact on product safety.
More specifically, it is a component that, if it fails, could create a hazardous situation. That could mean:
Electric shock
Fire or thermal hazard
Mechanical injury
Software malfunction
Incorrect information presented to the user
During safety evaluation, these components are not treated like any other BOM line. They are:
Checked against relevant standards (UL, IEC, EN)
Verified to be used within their stipulated limits
Documented in a List of Critical Components (LoCC), also known as a Critical Components List (CCL) or Constructional Data Form (CDF)
One significant nuance is that criticality is design-dependent.
Some typical critical component examples are power supplies, fuses and connectors. In general however, a component that is safety-critical in one product may not be critical in another. It depends entirely on whether its failure can lead to a hazardous situation in your specific design.
If that sounds like risk management – it is. The identification of critical components is essentially a focused extension of your risk process.
The Critical Component List (CCL)
The critical component list should be established during the design phase – not as a late stage compliance exercise before certification. This way, you will avoid unnecessary, costly hardware revisions and market introduction delays. The difference can be many months in time to market and hundreds of thousands of euros in total development + certification cost.
For each identified critical component, you need enough detail to clearly identify and justify its use, typically including:
Manufacturer
Part number
Technical data
Applicable safety standards
Valid third-party certificates
Confirmation that the component is used within its stipulated limits
External test houses rely on this information. If a component is already third-party evaluated, it reduces testing effort, cost and avoids unnecessary repetition.
Two recurring risks to watch for:
The component is certified – but used outside the scope of its limits.
The manufacturer decides not to renew certification, and you discover it too late.
If a critical component lacks certification, you can pay for testing yourself. However, the cost is usually significant and there is no guarantee the component actually passes the test. Selecting a certified alternative early in the design phase is often the more robust approach.
Different roles, different meanings of "critical"
Within a company, different roles may argue that different components are critical. Purchasing departments might say a component is critical from a sourcing perspective and a customer may view a part as critical due to functionality or aesthetics, such as color.
Under standards such as IEC 60601-1 or IEC 62368-1, a component is critical only if it affects product safety. That distinction becomes important during audits and external reviews. Essentially, the critical component list is a safety document.
Ending notes
Thank you for reading the first post in our Critical Components series – we hope it provided useful clarity and insights. In the next article, we'll take a closer look at how to identify critical components, followed by lifecycle management: how to keep your critical component list up to date, and many more insights.
Do you have any questions about what you read today, or suggestions for future topics? We'd be happy to hear from you. Feel free to reach out at info@orderlypeople.se or connect with us on LinkedIn.
Read more about Certainli here.