You can try downloading the IEC 60038 standard from the following sources:
This article provides an in-depth look at the IEC 60038 standard, explains why it is critical for modern infrastructure, details the voltage ranges it covers, and offers guidance on how to legitimately obtain the PDF version of the document. iec 60038 standard voltages pdf download
Electricity does not care about borders, but equipment does. The difference between 380V and 400V might be 5%, but the difference between compliance and a blown transformer is the . You can try downloading the IEC 60038 standard