IEC 60038:2009+A1:2021 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. This seventh constitutes a technical revision. The significant technical changes are:

- the addition of the values of 230 V (50 Hz) and 230/400 V (60 Hz) to Table 1;

- the replacement of the utilization voltage range at LV by a reference to the relevant standard and an informative annex;

- the addition of the value of 30 kV to Table 3;

- the replacement of the value of 1 050 kV by 1 100 kV in Table 5.

It has the status of a horizontal standard in accordance with IEC Guide 108.