"This part of IEC 60079 specifiesalternative requirements for construction@ test and marking for electrical equipment that provides Equipment Protection Level (EPL) Ga when single standardised Types of Protection (e.g. Ex ""ia"" @ Ex ""ma""@ Ex ""da"") cannot be applied. This standard also applies to equipment mounted across a boundary where different Equipment Protection Levels may be required. EXAMPLE: Equipment installed in the wall of a storage vessel containing Zone 0 (requiring EPL Ga) inside an area defined as Zone 1 (requiring EPL Gb). This electrical equipment@ within the operational parameters specified by the manufacturer@ ensures a very high Level of Protection that includes raremalfunctions related to the equipment or two malfunctions occurring independently of each other. NOTE A malfunction may result from a failure of the component parts of the electrical equipment or from anticipated externally applied influences. Two independent malfunctions which may occur more frequently and which@ separately@ would not create an ignition hazard but which@ in combination@ could create a potential ignition hazard@are regarded as occurring together to form a raremalfunction. This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0@ the requirement of this standard takes precedence."