Each piece of equipment and protective system must be marked in a clear and identifiable manner with the following minimum data:

• manufacturer’s name and address
• CE marking and number of Notified Body responsible for testing
• designation of the series and of the type
• serial No. when required
• the year of construction
• the particular Ex marking which means prevention of explosion in conjunction with the marking referring to the category.
• the letter “G” for the group of apparatus II for areas with the presence of explosive gas, vapour, mist with air mixtures
• and/or the letter “D” for areas where an explosive atmosphere can be built up caused by dust
• In addition and where required, also any details or certification code that are indespensable for the safety of operation will have to be affixed, i.e. also the normal CENELEC marking, e.g. EEXE eib IIC T4

Graphic examples are compliments of the The Wolf Safety Lamp Company Ltd., Sheffield, England