Specifies general requirements for construction, testing and marking of electrical apparatus for explosive gas atmospheres. Applies to electrical apparatus where atmospheric conditions for the explosion characteristics of the explosive gas atmosphere are considered as having pressures in the range 80 kPa (0.8 bar) to 110 kPa (1.1 bar) at a temperature in the range -20°C to +60°C. Atmospheric conditions outside this range may need special consideration. Does not apply to devices whose stated electrical parameters do not exceed any of the values 1-2 V, 0.1 A, 20 µJ or 25 mW, which need not be certified or marked as required by IEC 79. However, such devices are subject to the requirements of the various parts of IEC 79 if they are connected to a device which contains a source or a storage element of electrical energy which could cause the circuit to exceed these parameters. Supersedes IEC 79-8 and 79-9.