BS EN 60079-26:2004 specifies the particular requirements for construction, test and marking for electrical apparatus of Group II intended for use in Zone 0 as defined in BS EN 60079-10:2003.
This electrical apparatus, within the operational parameters specified by the manufacturer, ensures a very high level of protection that includes rare faults related to the apparatus or two faults occurring independently of each other. This electrical equipment is intended for use in Zone 0 hazardous areas, in which explosive gas atmospheres caused by mixtures of air and gases, vapours or mists under normal atmospheric conditions are present continuously, frequently or for long periods.
BS EN 60079-26:2004 also applies to apparatus mounted across the boundary between Zone 0 and Zone 1. For example, in the wall of a storage vessel. And applies to apparatus installed outside Zone 0, but electrically connected to apparatus inside Zone 0 (associated apparatus).
This standard supplements the general requirements in BS EN 60079-0 and the requirements of the standardized types of protection, in accordance with the BS EN 60079 series, to adapt the level of safety provided by those standards to the very high level of risk in Zone 0.
BS EN 60079-26:2004 will supersede BS EN 50284:1999 which will remain current as obsolescent on publication.