This invention relates to a staple for carrying and guiding or fixing a wire to a wall edge, for example a girder flange. This staple is composed of two wide branches 1 and 2, linked together at one of their ends, constituting jaws which may clamp a wall 8 whose thickness is slightly greater than their spacing. This staple is characterised essentially in that it is equipped with a groove 5 in a plane transverse to the branches 1 and 2. This groove passes through at least one of these two branches and the latter are provided on their opposing sides with means for increasing the friction between them and the said wall in a selective fashion along the direction of relative movements between them. <IMAGE>
