A junction box includes inputs and outputs, and electronic elements for distributing electric power, received at an input from a power source of a vehicle, to the outputs to provide power to loads of the vehicle which are connected to the outputs. The electronic elements include semiconductor switches operable for distributing the power to the loads via the outputs. A first controller controls operating conditions of the switches and adjusts operative cycles of the switches to the number and type of loads. The first controller is programmable according to features of the vehicle in terms of the amount and type of loads. A monitor may monitor the loads and be associated with a processor and a second controller for controlling the operating conditions of the switches to dynamically and automatically adjust the operative switch cycles to the demands of the loads according to a shaping thereof performed by the processor.