The invention concerns a winding head isolation element (1) with a body (2, 3) having a first longitudinal side (5), a second longitudinal side (6), a first transversal side (7) and a second transversal side (8), and a tongue portion (9) projecting from the first longitudinal side (5), the body (2, 3) and the tongue portion (9) being made of a flat material. It is endeavored to keep the efforts and costs for the mounting of the isolation element on a winding head small. For this purpose, the body (2, 3) is deformable around an axis (4) extending transversely to the tongue portion (9) and has at least one opening (21, 22) extending transversely to the tongue portion (9), said tongue portion (9) being adapted for insertion through the opening.