A grounding brush assembly includes a brush having a plurality of conductive fibers and a support having a mounting portion housing conductive fibers and first and second lateral lips extending from the mounting portion and axially gripping the conductive fibers. The assembly includes a mounting plate connected with the support and provided with at least one radial portion extending radially outwardly from the mounting portion of the support. The mounting plate has an axial portion extending axially from the radial portion, at least partly radially surrounding the mounting portion of the support and being spaced radially apart radially from the mounting portion. Further, a retaining portion extends radially inwardly from the axial portion.