A shelf support system includes an upright having: a profile-member made of electrically conductive material and comprising a cavity, an insulating element made of a first electrically insulating material and configured to be inserted in the cavity of the profile-member and comprising a housing, a rack made of electrically conductive material and comprising a connection structure configured to connect a shelf to the shelf support system, and a power supply device configured to supply electrical power to the rack. The rack is configured to be inserted in the housing of the insulating element so that the insulating element is interposed between the rack and the profile-member in order to prevent a passage of electric current from the rack to the profile-member. The connection structure of the rack includes a hole configured to be connected to a connection element associated with the shelf.