What Goes in a Technical File

A technical file is the evidence behind your CE mark: the drawings, test reports and risk assessment that prove the claim your Declaration of Conformity makes on a single page. Get it wrong and the mark is unsupported, whatever it looks like on the box. National authorities validated 4,671 Safety Gate alerts across the EU in 2025, the highest number since the system began in 2003, and a large share end with an authority asking for exactly this file. Here is what has to be in it, how long to keep it, and who can knock on the door asking for a copy.

What is a technical file for CE marking?

A technical file (sometimes called technical documentation, or a technical construction file under older directives) is the complete record a manufacturer compiles to demonstrate that a product meets every essential requirement of the legislation it falls under. It is not shipped with the product and it is not public. It sits with the manufacturer, or their authorised representative, ready to be produced the moment a market surveillance authority asks a reasoned question about the product's safety or conformity.

Think of the Declaration of Conformity as the signature and the technical file as everything the signature is backed by. The DoC is one page that lists which directives apply and which standards were used. The technical file is the underlying proof: the drawings that match the physical product, the test lab reports, the risk assessment, and the records showing how the factory keeps making the same thing it tested. Our glossary entry on technical files covers the short definition; this piece goes into what actually has to sit inside one.

What has to be inside it

The exact list varies slightly by directive, but the core content is consistent across the New Legislative Framework acts that use CE marking (Low Voltage, EMC, Radio Equipment, Machinery, Toy Safety and the rest). The table below shows what most manufacturers need to assemble, and why each piece matters.

A few of these deserve a closer look. The risk assessment is the piece most often missing or thin, and it is also the one an inspector reads first, because it shows whether the manufacturer actually thought about failure modes rather than just running a standard test and moving on. Test reports need to be traceable to the exact product variant: a report for a 5V version of a charger does not cover a 12V variant with a different transformer, even if the housing is identical.

How long do you have to keep a technical file?

Ten years. Under the harmonisation directives (the EMC Directive, for instance, states in Article 7(3) that manufacturers "shall keep the technical documentation and the EU declaration of conformity for 10 years"), the clock runs from when the apparatus is placed on the market, and in practice that means keeping the file for 10 years after the last unit of that model leaves the factory, not 10 years from your first production run. If you sell a product line for six years and then discontinue it, you are still on the hook for documentation until year sixteen.

This has a practical consequence people underestimate: staff turnover, company acquisitions and cloud storage migrations all happen well within that window. A technical file that lives on one engineer's laptop, or in a format only one now-departed contractor understood, is a real liability. Store it somewhere the business will still be able to open in a decade, with version control that shows which file matched which production run.

Who can demand to see it, and how fast do you have to respond?

Market surveillance authorities are the ones with the legal power to ask, and our market surveillance regulation guide covers the wider framework. Under Regulation (EU) 2019/1020, economic operators must, "further to a reasoned request from a market surveillance authority," provide all the information and documentation needed to demonstrate a product's conformity, in a language the authority can easily understand (Article 4(3)(b)), and authorities can require documents, technical specifications, data or information on compliance "in any form or format" (Article 14(4)(a)). The regulation itself does not fix a single EU-wide number of days for every case; the deadline is set in the authority's own request, and guidance for suppliers notes that manufacturers and importers are frequently given as little as 10 working days to produce a complete file, particularly where a safety concern has already been flagged.

Say you're a small UK company selling a smart plug through a marketplace, and a customer complaint about overheating reaches Trading Standards. A request for your technical file, in English, with a short deadline, is a normal first step, not an unusual escalation, and it can arrive well after you stopped actively selling the product, since the file has to be available for the whole 10-year retention period. If the paperwork cannot be produced quickly, or turns out not to match the product actually on sale, that alone is often treated as equivalent to non-compliance, whatever the test results underneath would have shown. Authorities do not need to prove the product is unsafe to open an investigation; an incomplete or unavailable technical file is grounds enough to escalate.

Building one file that covers every variant, without duplicating work

Most product ranges are not single items, they are families: the same core electronics in three colours, two voltage options, or a handful of regional radio bands. Rebuilding a full technical file from scratch for every SKU wastes time and, worse, invites drift, where one variant's file quietly falls out of sync with the actual hardware.

The more efficient pattern is a master file for the product family, with a short variant annex for each specific model. The master file carries everything genuinely shared: the general design description, the risk assessment methodology, the standards applied, and the conformity assessment procedure. Each variant annex then carries only what's different: its own test report if the electrical design changed, its own drawing revision, its own radio band declaration if relevant. This keeps the bulk of the work in one place and makes it obvious, at a glance, which parts of the file are variant-specific and need updating when you tweak a design.

A few habits make this easier to sustain. Tie every drawing and test report to a specific revision number, not just a date, so a hardware change automatically flags which documents are now stale. Keep the risk assessment as a living document that gets revisited on every material design change, not written once at launch and left untouched. And treat the Declaration of Conformity as the last thing you produce, not the first: it should be a straightforward summary of a technical file that already exists, not a promise you're writing ahead of the paperwork that's meant to back it up. If you're still working out which legislation and standards actually apply before you get this far, our CE marking requirements guide is the place to start, and our free compliance checker will point you at the standards relevant to your product category.

Where this leaves your paperwork

None of this needs to be complicated once the structure is clear: description, drawings, standards, risk assessment, test reports, procedure, and the signed declaration on top. What trips manufacturers up is not the content, it's letting the file drift out of sync with the product, or losing track of who owns it as staff and storage systems change over a ten-year span. Build it once, structured so variants can be added without rewriting the shared parts, and it will still hold up if an authority asks in year nine. If you haven't yet worked out which standards and modules apply to your product, start with our CE marking requirements guide before you assemble the file itself.