This European Standard is applicable to new low voltage devices for measurement, control and protection which are: for indoor or outdoor fixed installations in traction systems, and operated in conjunction with high voltage equipment with an a.c. line voltage and frequency as specified in EN50163 . NOTE EN50163 specifies the a.c. traction systems 15kV 16,7Hz and 25kV 50Hz. This European Standard also applies to measurement, control and protective devices other than low voltage devices and not covered by a specific railway product standard as far as reasonably possible. Requirements of this document prevail.