IEC 60038IEC voltage range AC DC defining risk

High voltage > 1000 Vrms > 1500 V electrical arcing

Low voltage 50–1000 Vrms 120–1500 V electrical shock

Extra-low voltage < 50 Vrms < 120 V low risk

International Standard IEC 60038 defines a set of standard voltages for use in low voltage and high voltage AC electricity supply systems.

Low voltageWhere two voltages are given below separated by “/”, the first is the root-mean-square voltage between a phase and the neutral connector, whereas the second is the corresponding root-mean-square voltage between two phases. The three-phase voltages are for use in either four-wire (with neutral) or three-wire (without neutral) systems.

Three-phase 50 Hz• 230 V / 400 V

• 400 V / 690 V

• 1000 V

Suppliers using 220 V / 380 V or 240 V / 415 V systems were expected by the standard to migrate to the recommended value of 230 V / 400 V by the year 2003. This migration has already been largely completed, as least within the European Union.

Three-phase 60 Hz• 120 V / 208 V

• 240 V

• 277 V / 480 V

• 480 V

• 347 V / 600 V

• 600 V

One-phase, three-wire 60 Hz• 120 V / 240 V