# IEC 60038

IEC voltage range AC RMS
voltage
(V)
DC voltage (V) Defining risk
High voltage > 1 000 > 1 500 Electrical arcing
Low voltage 50 to 1 000 120 to 1 500 Electrical shock
Extra-low voltage < 50 < 120 Low risk

International Standard IEC 60038:1983 defines a set of standard voltages for use in low voltage and high voltage AC electricity supply systems.

## Low voltage

Where 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 (exception: the category shown below called "One Phase", where 240 V is the root-mean-square voltage between the two legs of a split phase). 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 (formerly 220/380V)
• 400 V / 690 V (formerly 380/660V)
• 1000 V (3 wire)

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, at least within the European Union.

### Voltage conversion schedule

Year Neutral-Phase [V] / Phase-Phase [V]
— 1987 220 V / 380 V – 10% .. +10% [1]
1988 — 2003 230 V / 400 V – 10% .. + 6% [1]
2003 — 230 V / 400 V – 10% .. +10% [1]

### Three-phase 60 Hz

• 120 V / 208 V
• 240 V
• 277 V / 480 V
• 480 V
• 347 V / 600 V
• 600 V / 1000 V

### One-phase, three-wire 60 Hz (American split-phase)

• 120 V / 240 V

## Medium voltage

Table 3 of IEC 60038 lists nominal voltages above 1 kV and not exceeding 35 kV. There are two series, one from 3 kV up to 35 kV and another one from 4.16 kV up to 34.5 kV.

## High voltage

Table 4 shows nominal voltages above 35 kV and not exceeding 230 kV.

## Extra-high voltage

Table 5 is systematically different, as the highest voltage for equipment is the characteristic value exceeding 245 kV, the enumeration begins at 300 kV and ends with 1200 kV.