Constructional and test requirements for electrical apparatus, parts of the apparatus and Ex components with rated voltages not exceeding 11 kV. Supplements BS 5501-1:1977.
BS 5501-8:1988 history
2015BS EN 60079-18:2015 Explosive atmospheres. Equipment protection by encapsulation "m"
2010BS EN 60079-18:2009 Explosive atmospheres. Part 18: Equipment protection by encapsulation "m"
2004BS EN 60079-18:2004 Electrical apparatus for explosive gas atmospheres. Construction, test and marking of type of protection encapsulation "m" electrical apparatus