The present invention relates to electric switching devices, and more specifically to the arc-quenching chambers of such devices, comprising metal De-Ion plates. The arc-quenching chamber disclosed comprises a De-Ion grid composed of metal plates which are arranged in parallel planes, have the shape of an S, and are joined pairwise by a currentconducting neck; the minor arcs circulate between said plates; said plates have U-shaped projections at the entrance of the arc to said grids and are pairwise joined by a neck at the central part.