Nowadays, only 3x400V+N grids are installed in Belgium by the distribution system operators. However, there are still some places, especially in large cities, where the 3x230V network is still available. About 20 - 30% of household installations in Flanders and Brussels are connected to a 3x230V network.

In installations connected to a 3x230V network, problems may occur when charging certain types of electric vehicles. In a 3x400V+N network, consumers are always connected between the neutral conductor and a line wire, so that there is always a contact socket whose voltage between the contact socket and the earth is approximately equal to 0V. However, in a 3x230V network, consumers are connected between two line wires, which means that such a contact socket is not always present. Since such 3x230V networks are not standard in the rest of Europe and America, some electric vehicles consider the situation in which there is no socket at earth potential as "faulty", which means they will not charge.

This charging problem can be solved by installing an isolation transformer. After installing an isolation transformer, regardless of the type of existing network, a new network is started where there is a contact bus at earth potential.