arcuate and annular bump r1 in the base to cause the molded base material to flow in directions to provide an effective seal while the apparatus hereinbefore described is effectively adapted to fulfill the objects stated it is to be understood that the invention is not intended to be confined to the particular preferred embodiment of terminal seal for electric switch disclosed inasmuch as it is susceptible of various modifications without departing from the scope of the appended claims for example while the improved sealing structure has been illustrated in connection with a stationary contact shank and a movable contact support connector it will be apparent that a similar sealing structure could be used for sealing metal cover 4 to base 2 for this purpose the upper portion of the base could be provided with a step extending with gradual curvature in a closed loop within and around the rim of the base with the shoulder at such step having a bump throughout such closed loop that is rounded in cross section similar to that shown in fig2 in other words such step or groove within the rim of the base would have rounded corners that is gradual curvature rather than sharp corners of a rectangular base or the base could be oval or oblong in interior and or exterior configuration also for this purpose the metal cover would be cast or formed with a contiguous closed loop drop complementary to such step.