This document specifies requirements for, and constructions and dimensions of, single core cables, rated voltage U0 / U = 300 /300 V, of the following type: Unscreened (0,5 mm2 to 2,5 mm2 single core) These cables are rated for occasional thermal stresses causing ageing equivalent to continuous operational life at a temperature of 105 °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/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. Under fire conditions the cables exhibit special performance characteristics in respect of maximum permissible flame propagation (flame spread) and maximum permissible emission of smoke and toxic gases. These requirements are specified to permit the cables to satisfy Hazard Level 3 of EN 45545 1 and EN 45545 2. EN 50306-2:2020 is expected to be used in conjunction with EN 50306-1:2020, General requirements.