Abstract: Distribution network planning is the basis to guarantee reliable operation of "Coal to Electricity"('C2E') distribution network. While, as a kind of incremental load, there is no standard about average transformer capacity for each 'C2E' consumer. As a result, 'C2E' distribution network planning and design lacks basic rules. Aimed at this problem, a method named ‘Heat load to Electricity load’ for calculating 'C2E' incremental load and average transformer capacity per consumer was proposed in this paper, which provides basis to 'C2E' distribution network and electrical equipment selection. With this method, 'C2E' electrical load and average transformer capacity is determined by heating load of building in demand side. An example with typical residential building in Beijing was taken in this paper. Heating load of building was calculated using DeST (Designer's Simulation Toolkits) firstly. Then, with the kind of electrical heating equipment, average transformer capacity for each 'C2E' consumer in Beijing rural area was given.