A household appliance comprising: an internal box including walls; a shelf comprising a frame physically associated with the walls of the internal box the frame comprising side portions, a front portion and a rear portion; at least one accessory physically associated with the shelf; accessory rails proximate the shelf, the accessory rails defining at least one track for displacement of the at least one accessory; wherein the frame comprises a plurality of receiving structures; wherein the accessory rails include engaging projections which cooperate directly with the plurality of receiving structures of the frame so that the accessory rails are removably fitted with the receiving structures, wherein the receiving structures are defined by an opening contour that delimits an aperture, wherein at least one latching hole is provided in the opening contour; and each of the engaging projections of the accessory rails includes at least one main portion which, when the accessory rails are assembled, extends in the direction of the aperture and at least one quick-fitting latch capable of engaging the at least one latching hole, the at least one quick-fitting latch extending transversely from the main portion, wherein at least two side accessory rails engage the receiving structures arranged adjacent to the side portions of the frame and at least one central accessory rail engages with at least one central receiving structure arranged adjacent the front portion and the rear portion of the frame, wherein each of the at least two side accessory rails and the at least one central accessory rail comprises, respectively, at least one upper flange and at least one lower flange joined together by a main wall, wherein the at least one track is arranged in the space adjacent to the at least one upper flange, the at least one lower flange, and the main wall; and wherein the at least two side accessory rails comprise respective main portions of engaging projections extending transversely from the main walls, respectively, and the at least one central accessory rail comprises respective main portions of engaging projections extending longitudinally from the front and rear ends of the at least one upper flange, respectively. an internal box including walls; a shelf comprising a frame physically associated with the walls of the internal box the frame comprising side portions, a front portion and a rear portion; at least one accessory physically associated with the shelf; accessory rails proximate the shelf, the accessory rails defining at least one track for displacement of the at least one accessory; wherein the frame comprises a plurality of receiving structures; wherein the accessory rails include engaging projections which cooperate directly with the plurality of receiving structures of the frame so that the accessory rails are removably fitted with the receiving structures, wherein the receiving structures are defined by an opening contour that delimits an aperture, wherein at least one latching hole is provided in the opening contour; and each of the engaging projections of the accessory rails includes at least one main portion which, when the accessory rails are assembled, extends in the direction of the aperture and at least one quick-fitting latch capable of engaging the at least one latching hole, the at least one quick-fitting latch extending transversely from the main portion, wherein at least two side accessory rails engage the receiving structures arranged adjacent to the side portions of the frame and at least one central accessory rail engages with at least one central receiving structure arranged adjacent the front portion and the rear portion of the frame, wherein each of the at least two side accessory rails and the at least one central accessory rail comprises, respectively, at least one upper flange and at least one lower flange joined together by a main wall, wherein the at least one track is arranged in the space adjacent to the at least one upper flange, the at least one lower flange, and the main wall; and wherein the at least two side accessory rails comprise respective main portions of engaging projections extending transversely from the main walls, respectively, and the at least one central accessory rail comprises respective main portions of engaging projections extending longitudinally from the front and rear ends of the at least one upper flange, respectively.