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). 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. 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.