EN 50306-1 specifies the general requirements applicable to the cables given in EN 50306-2, EN 50306-3 and EN 50306-4. It includes the detailed requirements for S2 sheathing materials and other components called up in the separate parts. NOTE – Detailed requirements for insulation systems are given in EN 50306-2. In particular, EN 50306-1 specifies those requirements relating to fire safety which enable the cables to satisfy Hazard Level 3 of EN 45545-1 and EN 45545-2. These cables are rated for occasional thermal stresses which causes ageing equivalent to continuous operational life at a temperature of 105 °C or 90 °C. For standard cables, this is determined by the acceptance test defined in EN 50305, using accelerated long-term (5 000 h) thermal ageing indicating a 125 °C or 110 °C /20 000 h temperature index. If the customer were to require lifetime predictions, this would be demonstrated based on the temperature index of the product as supplied by the manufacturer. The maximum temperature for short circuit conditions is 160 °C based on duration of 5 s. EN 50306-1 is expected to be used in conjunction with one or more of the other parts of EN 50306.