Abstract: An electric switching apparatus of the type including a base fabricated of electrical insulation material and a switching mechanism cage which includes at least two side plates. Outwardly extending projection members are disposed at opposite ends of at least one edge of each of the side plates, and each include a hook portion at the end thereof which extends outwardly from the lateral edges of the plates. The apparatus base includes recesses extending therethrough which receive the projection members, and the hook portions project therefrom when the projection members are disposed in the recesses. Spring clips are disposed between the hook portions of the plate projection members and the apparatus base for fastening the cage side plates to the base.