scope:

This publication applies to - a.c. transmission, distribution and utilization systems and equipment for use in such systems with standard frequencies 50 Hz and 60 Hz having a nominal voltage above 100 V; - a.c. and d.c. traction systems; - a.c. and d.c. equipment having nominal voltages below 120 V a.c. or below 750 V d.c., the a.c. voltages being intended (but not exclusively) for 50 Hz and 60 Hz applications; such equipment covers batteries (from primary or secondary cells), other power supply devices (a.c. or d.c.), electrical equipment (including industrial and communication), and appliances. This publication does not apply to voltages representing or transmitting signals or measured values. This publication does not apply to standard voltages of components and parts used within electrical devices or items of equipment. This publication specifies standard voltage values which are intended to serve - as preferential values for the nominal voltage of electrical supply systems, and - as reference values for equipment and system design.