CE marking is not applicable for power and distribution transformers according to the Low Voltage Directive 2006/95/EC.
The Low Voltage Directive 2006/95/EC concerns low voltage equipments used within certain voltage limits, including those used in the manufacture of power transformers such as control units, wiring cabinet, etc ...
Such equipments, when purchased from the European Union area, should respect this directive and carry the CE marking.
However power transformers, in themselves, are not subject to such marking as these high voltage equipments don’t fall within the scope of the Directive.
The power and distribution transformers, housed in locked locations not accessible to the public and exclusively reserved for use by advised and trained persons, are therefore not covered by the Low Voltage Directive and therefore require no EC marking.
There are 2 exceptions of CE marking which applies to transformers below;
1. ATEX Explosive area transformers according to the directive 94/9/EC
2. Ecodesign transformers according to the directive 2009/125/EC