What We Do We transmit, distribute and connect electricity to and from 3.5 million homes and businesses over our network, 24 hours a day, every day of the year. Our distribution network has: Our distribution network has 30,000 substations, supplying 3.52 million customers; 40,000km of overhead lines (that's enough to wrap once around the world); and 65,000km of underground cables - all to keep your electricity flowing." How we keep the electricity flowing: 1) SP Transmission: Power station - transmitted around the country at 275,000 or 400,000 volts. Grid Supply point converts to 132,000 volts. Large sub-station converts to 33,000 volts. 2) SP Distribution - Primary sub-station converts to 11,000 volts. Secondary sub-station converts to 415/230 volts. 3) Electricity Supplier- Electricity meter - Our customers 230 volts Delivering Value to Customers For a domestic customer the average cost is just 35p per day, much less than a 2nd Class postage stamp, a coffee shop latte, or a typical domestic broadband service. We take electricity generated from wind farms, power stations, and other utilities, reduce it to the low voltage needed for homes and transport it through our vast network.