arpadveress 
Where no certificate of conformity (or the origin of a certificate cannot be verified) is available, a fitness-for-purpose assessment should be undertaken. Usually this will require a full audit and assessment of the equipment, generation of a design specification including all necessary calculations, measurements, equipment and cable parameters and the like, and making decisions and statements that the equipment is fit for its purpose and safe to use. Where tests are required they should be carried out by a competent person using the necessary calibrated test equipment.
In order to establish evidence enabling a risk assessment to demonstrate an equivalent level of safety within an existing installation, the need for a fitness-for-purpose assessment report may be determined on the basis that insufficient information is available to comply with 4.3 of IEC 60079-14:— or with the requirements of the installation standard applicable at the time of the original installation.
In preparing a fitness-for-purpose assessment it should be based on the assessment to standards that are relative to the avoidance of ignition sources for the equipment to be used in hazardous areas.
The assessment of the equipment should take into account any likely ignition sources, whether they be arcs, sparks or hot surfaces, and take into account whether they are likely to occur in normal circumstances or only under fault or abnormal conditions. Attention is drawn to the possibility of ignition from high energy light sources (lasers), static electricity, friction heating, ionising radiation etc., as well as the contact sparking and/or heating from electrical equipment. Where requirements for protective devices as a form of control are used they should also be included in the assessment.
Interesting question here: what about the one Ex non electrical installation manufactured before 30.06.2003?
Keep up good work!
Arpad
