Often there are other directives that need to be considered for plant and machinery, alongside the Machinery Directive. If a machine also contains electrical equipment, for example, then it will often fall under the scope of the Low Voltage Directive as well.
"For the purposes of this Directive, 'electrical equipment' means any equipment designed for use with a voltage rating of between 50 and 1 000 V for alternating current and between 75 and 1 500 V for direct current […]"
The Low Voltage Directive can be found on the homepage of the European Commission.