The Technical File

With the exception of the EMC Directive, all CE marking directives require the manufacturer of the product to create a technical file which should contain the information required to show that the product properly complies with the requirements of the directives which apply to it.

The EMC Directive provides for a Technical Construction File, but this is not the same thing as the file required by the other directives (see below).

The directives contain clauses which give some general details of the kind of information which will be required in the technical file, but this is couched in the most general of terms. As a general guide, the following items should be included:

• Description of the apparatus, usually accompanied by block diagram
• Wiring and circuit diagrams
• General Arrangement drawing
• List of standards applied
• Records of assessment to standards
• Description of control philosophy/logic
• Datasheets for critical sub-assemblies
• Part list
• Copies of any markings and labels
• Copy of instructions (user, maintenance, installation)
• Test reports
• Quality control & commissioning procedures
• Declaration of Conformity

There is nothing to stop the file containing a great deal more information than is listed here - for instance copies of the engineering drawings for any bespoke parts could also be included. However, these should not be used to pack the file at the expense of the more relevant information on how the equipment operates and how it meets the safety objectives of the Directive.

Of course, for simple products (e.g. household domestic appliances) the control philosophy may be so simple as to be self evident, in which case it is unnecessary for the file to include this information. Typically, this sort of product will be the subject of a notified body report confirming compliance to a harmonised standard and a copy of the report should be included in the file. The importance of including a basic general description of the appliance cannot be overstated. Furthermore, the action of providing a properly documented description of the control system will often allow the designer to spot potential flaws in the logic of the operation.

It is important to understand that only the authorities given power to enforce the directives have a right to see the technical file. It does not need to be published or given to customers. With the exception of the Medical Devices Directive, there is no clear requirement that the file should be kept on EU soil. However, for a manufacturer based outside of the EU, any approach made by the authorities will initially come to the authorised agent or the importer of the goods, so they must have access to the file to be able to fulfil their legal obligations. Access to technical information may also be a condition of contract laid down by some customers.

Different directives treat the creation of the file with different priorities. The LVD strictly requires the manufacturer to have the file in place before the CE mark is applied, whereas the Machinery Directive says that the file does not have to be in constant existence and thereby provides for a period of grace in which it can be compiled. In practice, it makes sense to ensure the file is created early in the life of a product and is then kept up to date.

EMC Technical Construction File

The EMC Directive does not currently contain a requirement for a technical file, although this may change in the future (a new draft of the Directive is being prepared at present). However, a technical justification for a claim of compliance is useful even where the standards route is used.

The EMC Directive refers to a 'Technical Construction File' (TCF) as one of the routes of compliance. The TCF has a legal status peculiar to the EMC Directive, and is used in two situations:

• where no applicable harmonised standards exist. This is very unusual, since there are many standards including the generic documents which apply wherever there are no more specific standards;
  
  
• where the product fails to comply with the requirements of the standards but nevertheless the manufacturer argues that the essential requirements of the directive are still met and therefore the product should be CE marked.
  

In both cases, the manufacturer can provide a written technical argument for why they believe that their product complies with the essential requirements of the directive. However, clearly this argument must be based on sound technical reasoning, and to ensure that the manufacturer is not simply using the TCF as an excuse for poor design or EMC performance, the file must be checked by a Competent Body to verify that the claim of compliance is reasonable and based on sound engineering judgement.