The sizing and the distribution of the circuits, equipments of illumination and wall sockets of a household building are planned to offer a certain comfort to the users. The comfort is associated to a psychological state of welfare and depends on an ample amount of factors. The residences consume about 26% of the total electric energy in Sao Paulo state and the tasks aimed to the optimization of the energy use must consider the household use. Currently, the Brazilian market of electric energy grows to a tax of 4.5% per year and during the last decades, the consumption of electrical energy presented superior tables of expansion to the gross domestic product (GDP). This growth showed up larger the household, commercial and agricultural consumers. The standards of comfort and performance change as the time goes by, with the incorporation of new technologies. The number of household appliances has been increased by the years, as well as the use of new equipments, demanding alterations in the electric projects to attend to this comfort of use. (c) 2004 Elsevier B.V. All rights reserved.