CE marking is mandatory for products covered by one or more CE marking directives. Here are a few examples:
RoHS Directive
Low Voltage Directive
EMC Directive
Toy Safety Directive
Personal Protective Equipment Directive
These directives provide general safety requirements applicable to the products. Importers and manufacturers must then identify the relevant harmonised standards for their products. Lab testing is then conducted to verify if the product is compliant with the relevant harmonised standards.