A control module for an electric switch comprising: a body part, a main control shaft, an operating shaft and a drive system operationally connecting the main control shaft to the operating shaft such that the operating shaft is adapted to be rotated by the main control shaft. Rotation axes of the main control shaft and operating shaft are perpendicular to each other. The body part comprises a first side wall, a second side wall, a top wall and a bottom wall. The bottom wall is provided with a bottom recess adapted to receive a portion of an add-on, a bottom part of the main control shaft being accessible through the bottom recess.