Deliverable

EN 50306-4 specifies requirements for, and constructions and dimensions of, multicore and multipair cables rated 300 V to earth, of the following types: - unscreened, sheathed for either exposed or protected wiring (0,5 mm2 to 2,5 mm2, number of cores from 2 to 48); - screened, sheathed for either exposed or protected wiring (0,5 mm2 to 2,5 mm2, number of cores from 2 to 8); - screened, sheathed for either exposed or protected wiring (0,5 mm2 to 1,5 mm2, number of pairs of cores from 2 to 7). NOTE 1 Not all conductor sizes/number of cores are specified for every type. All cables have stranded tinned copper conductors, halogen-free, thin wall thickness insulation and standard wall thickness sheath. Cable types are specified for use in exposed situations (Class E), and for protected situations (Class P). They are for use in railway rolling stock as fixed wiring, or wiring where limited flexing in operation is encountered. The requirements provide for a continuous operational life at temperatures of 90 °C or 105 °C dependent upon the sheath system type. NOTE 2 In EN 50306-4 the higher temperature rating of 105 °C is only allowed where sheath type S2 is used, and where it has been specifically tested for the higher rating (i.e. by long-term thermal endurance testing to demonstrate a lifetime of at least 20 000 h at 125 °C). The maximum temperature for short-circuit conditions of 160 °C is based on a duration of 5 s. The cables specified in EN 50306-4 which have a sheath of type EM 101, EM 103 or S2 material are suitable for operation at temperatures as low as – 25 °C and those with sheath of type EM 102 or EM 104 material are suitable for operation at temperatures as low as 40 °C. NOTE 3 Where fuel oil is present sheath types EM 101 and EM 102 are not suitable. NOTE 4 S2 material may also be suitable for operational temperatures as low as –40 °C, but if so must be tested accordingly to confirm this. 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 Levels 2, 3 or 4 of EN 45545-1 ). NOTE 5 Requirements for the emission of smoke and gases are not specified for cables used for Hazard Level 1 of EN 45545-1. NOTE 6 EN 45545-1 is still under development and should be consulted. EN 50306-4 should be used in conjunction with EN 50306-1, General requirements, EN 50306-2, Single core cables, and EN 50306-3, Single core and multicore cables.