As part of a study to determine the factors influencing the power usage patterns of domestic consumers, electrical loads have been logged at half- and quarter-hourly intervals for several months. This enables the production of hundreds of daily load profiles, the shapes of which can be analysed with respect to various attributes of the consumers. However, in order to carry out such an analysis, it is necessary to find a numerical representation of a load shape. It is found that the most suitable means of doing so is to calculate Fourier series approximations to the profiles, and use the coefficients of the series to represent the profile shapes.