Regulation and sustainability
Changing a component in a certified product
A supplier discontinues a part, you buy the equivalent and carry on selling. The paperwork still describes the old one.
It happens in every company that makes something: a part stops being supplied, you buy the equivalent from the next catalogue and the line keeps running. Nobody did anything odd — it is the sensible call to avoid stopping. The problem shows up months later, when someone compares what is inside the product with what its papers say.
The four kinds of change, from quiet to loud
| Change | What it usually means |
|---|---|
| Same maker, same part number, different batch | Nothing: this is the normal case |
| Same maker, successor part number | Check their data still covers your claims |
| Different maker, «equivalent» part | This is where the real work starts |
| A part touching safety, food contact or the electrical circuit | Stop and check before fitting a single unit |
Important
«Equivalent» is a purchasing word, not a quality one. **Two parts can be mechanically interchangeable and documentarily not**: same size, same function, and behind them a different certificate, a different material or a test run to another standard. The right question is never «does it fit?» but **«is what I declare about my product still true with this part inside?»**. The first is answered by the warehouse; the second by the technical file.
What to do on the day of the change, not the day of the problem
- 1
Ask the new supplier for the same documentation you held for the old one
If they cannot provide it, that is already your answer.
- 2
Compare it against what your product declares
Standard applied, material, limit values. Point by point, not from memory.
- 3
Record from which serial or batch the new part is fitted
Without that boundary you cannot contain anything if a review is ever needed.
- 4
And update the technical file before the first unit ships
After that it becomes archaeology.
Watch out
The scenario to avoid at all costs is the silent one: **the supplier makes the change and does not tell you**. Same part number, same delivery note, and inside a different material or a different factory. That is why the commitment to notify changes is requested IN WRITING when the supplier is onboarded and not once suspicions arise — and why it pays to keep each component's datasheet with its date: it is the only thing that lets you show what you were being supplied at any given time.
When the change does force new paperwork
Worth knowing
Which changes force repeat testing, a new declaration or notifying a body depends on the product and its regulatory framework. **Your adviser or notified body settles that before the part is fitted**; here we explain how not to arrive at that conversation with two hundred units already sold.
›Can I fit an equivalent part while I check?
It depends what it touches. If safety is anywhere near, the prudent answer is no.
›Does the whole product need recertifying?
Rarely. The norm is reviewing the affected part, and for that you need the file.
›What if the supplier changed it without telling me?
Document from when, assess the impact, and revisit the notification agreement with them.
A real case
The situation
Purchasing swaps in an equivalent part from another maker to keep the line running.
What you do
- Asks the new supplier for the same datasheet and certificate held for the old one
- Compares point by point against what the product declares
What you get
The change is decided on data rather than on «it fits the same».
The situation
Units already sold need reviewing and nobody knows since when the new part has been fitted.
What you do
- Records the serial or batch number from which each change applies
What you get
The review is contained to the affected units instead of a whole year's output.
The situation
A supplier changes factory without notice and you find out from a colour difference.
What you do
- Keeps each component's datasheet with its date and requires written change notification
What you get
You can show what was being supplied when, and claim against something written down.
The situation
A part is substituted and nobody touches the documentation.
What you do
- Reviews which documents describe that part
What you get
The papers keep describing what is made.
The situation
Nobody knows from which unit the component changed.
What you do
- Records from which batch the new part enters
What you get
You can say what each unit carried.
The situation
The new part's supplier provides no documentation.
What you do
- Requests it before starting to use it
What you get
The change does not leave a gap in the file.
This article answers
- changed a component do i need to recertify
- equivalent part certified product
- supplier discontinued a component
- when to redo the declaration of conformity