A system for analyzing electrical consumption of a site equipped with a plurality electrical equipment. The system comprises at least one sensor for periodic measurement of global consumption of the site by measuring current and voltage signals on at least one of the electrical phases upstream of the supply network for the site. The system comprises a processor for decomposing the global consumption of the site to individual consumption of each kind of electrical equipment based on a set of signatures with each signature has power load coefficients representing power loads of the corresponding electrical equipment. The system comprises a processor for optimizing the set of signatures and power load coefficients in comparing a calculated recomposition of the individual consumption with the measured global consumption to have a smallest difference of the comparison result, while respecting physical constraints of the set of signatures and the power load coefficients.