Abstract: An electrically conductive sandwich panel (10) supplies at least one electrical device to be pushed into the panel. The sandwich panel (10) has two electrically conductive layers (13, 15) insulated from each other and a layer (11) formed by a board (12, 14) insulated from said electrical layers. The board has two sheets (111, 112) of cardboard enclosing an electrically insulating material, such as plaster. Connectors are used to connect the electrically conductive layers to a power supply. The panel may be screw-fastened on a support by means of suitable screws and may be fitted with a suitable electrical device. A punch tool facilitates pushing the electrical device into the panel.