A modular separating box for light guides having a receiving chamber, and/or a sending chamber, and/or a connection chamber enclosed by individual doors is disclosed. The modular separating box has at least one wall with at least one movable plate. The modular separating box also has at least one connection panel that forms a wall of the receiver and/or sending chamber, where fastening elements for joining one modular separating box with successive modular separating boxes for creating a modular arrangement of modular separating boxes are located on the upper and/or lower and/or side surfaces of the box housing. The system of modular separating boxes for light guides contains a set of interconnected modular separating boxes.