1. A switch device comprising an electrically insulating housing having housing walls forming a chamber, a cover detachably mounted on the housing, at least one set of contacts within the housing and comprising stationary contacts and movable contacts movable between open and closed positions with the stationary contacts, means for moving the movable contacts, the stationary contacts for each set of contacts comprising contact structure having a contact portion, an intermediate portion, and a terminal portion, the cover and housing having mutually interfitting portions for clampingly retaining the stationary contacts in place within the chamber when the cover is in place on the housing, the stationary contacts being removable from the chamber when the cover is detached, the cover and housing forming an access opening through which the terminal portion extends, the mutually interfitting portions comprise a projection on the cover extending in the direction of insertion of the cover onto the housing, and the projection being in surface-to-surface contact with the intermediate portion of the stationary contacts.

5. A switch device comprising an electrically insulatinG housing having housing walls forming a chamber, a cover detachably mounted on the top surface of the housing, at least one set of contacts within the housing and comprising a stationary contact structure and a movable contact movable between open and closed positions with the stationary contact structure, the stationary contact structure comprising a contact portion, an intermediate portion, and a terminal portion, and the inner surface of the housing wall comprising surface means extending into the chamber for guiding the stationary contact structure into position within the chamber, the surface means comprising a vertically extending surface having a lower end portion inclined at an angle toward the inserted position of the stationary contact structure.

7. A switch device comprising a circuit breaker including an insulating housing having an access opening therein, a cover for the opening, a circuit breaker mechanism within the housing and comprising a plurality of sets of movable and stationary contacts, means on the cover for opening and closing the separable contacts, said means comprising a crossbar and a connecting element, the cover having an aperture therein and the connecting element being slidably mounted in the aperture, means detachably interlocking the crossbar to the connecting element and comprising one member of an interlock on one of the crossbar and connecting element, and the other member of an interlock being on the other of the crossbar and connecting element.

10. A switch device comprising a circuit breaker including an insulating housing having an access opening therein, a cover for the opening, a circuit breaker mechanism within the housing and comprising a plurality of sets of movable and stationary contacts, means on the cover for opening and closing the separable contacts, said means comprising a crossbar and a connecting element, the cover having an aperture therein and the connecting element being slidably mounted in the aperture, the crossbar being attached to the connecting element and having a projection extending from one end thereof, the housing having a slot extending in the direction of movement of the crossbar, the projection on the crossbar extending into the slot, and auxiliary switch mounted adjacent the insulating housing and comprising movable and stationary contacts therein, the movable contacts being operatively connected to a plunger, the plunger extending into the slot in the housing, and being movable by the projection on the crossbar when the crossbar is actuated.