In electrical engineering, especially in power grids and in electrical power engineering, the voltage ranges are classified. A distinction is made between low voltage, medium voltage, high voltage and extra high voltage.
Low voltages include alternating vol tages below 1,000 V and direct voltages below 1,500 V. This includes the mains voltage of 230 V for single- phase alternating current and 400 V for three-phase alternatingcurrent, which is common in low-voltage networks and in households. In addition to the mains voltage, low voltages below 50 V DC or 120 V AC also belong to the low-voltage category.
Above the low voltage are the medium voltages with values from 3 kV to 30 kV, above that the high voltages with values from 60 kV and 110 kV and above that the extra high voltages, which can be between 220 kV and 1.15 MV.