IEC 60079-18:2009 gives the specific requirements for the construction, testing and marking of electrical equipment, parts of electrical equipment and Ex components with the type of protection encapsulation "m" intended for use in explosive gas atmospheres or explosive dust atmospheres. This part applies only for encapsulated electrical equipment, encapsulated parts of electrical equipment and encapsulated Ex components where the rated voltage does not exceed 11 kV. The significant technical changes with respect to the previous edition are as follows: - Incorporation of level of protection "mc" - Equipment protection levels (EPL Ma, Ga, Da, Mb, Gb, Db, Gc, Dc) - Incorporation of the dust requirements - Incorporation of switching contacts for level of protection "ma".