A modular redevelopment system of a street lamp for public lighting which includes at least: i. one or more boxed elements which have the following characteristics: a. they are open both at the top and at the bottom, b. they are shaped to be stacked one on top of the other, c. the conformations of the edge of the upper opening and of the edge of the lower opening are substantially the same, so that, when stacked one on top of the other, said boxed elements form a larger compound boxed element d. they are designed to be hooked to the support structure of a street lamp by means of a hooking subsystem, in turn included in said boxed elements, e. the area of the side wall of said boxed elements where they are coupled to said hooking subsystem has a suitable hole to allow power cables coming from the public lighting system to enter the boxed element, f. inside said boxed elements there are vertical conducting elements which go from the lower opening to the upper one, so that, when two or more boxed elements are stacked one on top of the other, a continuous conductive line that crosses the entire compound box element is formed; ii. a bottom cover shaped to close the lower opening of the boxed element which is located further down; iii. a top cover shaped to close the upper opening of the boxed element that is higher up. i. one or more boxed elements which have the following characteristics: a. they are open both at the top and at the bottom, b. they are shaped to be stacked one on top of the other, c. the conformations of the edge of the upper opening and of the edge of the lower opening are substantially the same, so that, when stacked one on top of the other, said boxed elements form a larger compound boxed element d. they are designed to be hooked to the support structure of a street lamp by means of a hooking subsystem, in turn included in said boxed elements, e. the area of the side wall of said boxed elements where they are coupled to said hooking subsystem has a suitable hole to allow power cables coming from the public lighting system to enter the boxed element, f. inside said boxed elements there are vertical conducting elements which go from the lower opening to the upper one, so that, when two or more boxed elements are stacked one on top of the other, a continuous conductive line that crosses the entire compound box element is formed; a. they are open both at the top and at the bottom, b. they are shaped to be stacked one on top of the other, c. the conformations of the edge of the upper opening and of the edge of the lower opening are substantially the same, so that, when stacked one on top of the other, said boxed elements form a larger compound boxed element d. they are designed to be hooked to the support structure of a street lamp by means of a hooking subsystem, in turn included in said boxed elements, e. the area of the side wall of said boxed elements where they are coupled to said hooking subsystem has a suitable hole to allow power cables coming from the public lighting system to enter the boxed element, f. inside said boxed elements there are vertical conducting elements which go from the lower opening to the upper one, so that, when two or more boxed elements are stacked one on top of the other, a continuous conductive line that crosses the entire compound box element is formed; ii. a bottom cover shaped to close the lower opening of the boxed element which is located further down; iii. a top cover shaped to close the upper opening of the boxed element that is higher up.