Circuit breakers and switches enable the substation to be disconnected from the transmission grid or for distribution lines to be disconnected. Transformers step down transmission voltages, 35 kV or more, down to primary distribution voltages. These are medium voltage circuits, usually 600–35 000 V. OverviewElectric power distribution is the final stage in the. Electricity is carried from the to individual consumers. Distribution connect to the transmission system an. Electric power distribution become necessary only in the 1880s, when electricity started being generated at. Until then, electricity was usually generated where it was used. The first power-distri. Electric power begins at a generating station, where the potential difference can be as high as 33,000 volts. AC is usually used. Users of large amounts of DC power such as some,.