EN 50306-1 specifies the general requirements applicable to the cables given EN 50306-2, EN 50306-3 and EN 50306-4. It includes the detailed requirements for S1 and S2 sheathing materials and other components called up in the separate Parts. In particular EN 50306-1 specifies those requirements relating to fire safety which enable the cables to satisfy Hazard Levels 2, 3 or 4 of EN 45545-1 2). These cables are rated for occasional thermal stresses causing ageing equivalent to continuous operational life at temperatures of 90 °C or 105 °C dependent upon the sheath system type. These temperatures are based upon an acceptance test, using long-term thermal endurance ageing at 110 °C and 125 °C respectively, and extrapolation of data to 20 000 h. The maximum temperature for short circuit conditions is 160 °C based on a duration of 5 s. EN 50306-1 should be used in conjunction with one or more of the other parts of EN 50306.