This Technical Report applies to low-voltage installations with a nominal system frequency of 50 Hz in which the circuits consist of insulated conductors, cables or busbar trunking systems.It defines the different parameters used for the calculation of the characteristics of electrical wiring systems in order to comply with rules of HD 384/HD 60364.These rules are mainly the following: - current-carrying capacities of the conductors; - characteristics of protective devices in regard to protection against overcurrent; - verification of thermal stress in conductors due to short-circuit current or earth fault current; - fault protection (protection against ind