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BS EN 60079-15: 2010
Explosive atmospheres. Equipment protection by type of protection "n"

This standard specifies requirements for the construction, testing and marking for Group II electrical equipment with type of protection, "n" intended for use in explosive gas atmospheres.

This standard is applicable to non-sparking electrical equipment and also to electrical equipment with parts or circuits producing arcs or sparks or having hot surfaces which, if not protected, could be capable of igniting a surrounding explosive gas atmosphere. 

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BS EN 60079-18: 2009
Explosive atmospheres. Equipment protection by encapsulation "m"

This standard 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 standard applies only for encapsulated electrical equipment, encapsulated parts of electrical equipment and encapsulated Ex components where the rated voltage does not exceed 11 kV.

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