Patent ID: 7704105

Claim:
An installation switch having an insulating housing and a terminal connecting arrangement for clamping a connecting conductor having an annular terminal shoe, the terminal connecting arrangement comprising: a terminal socket having an interior disposed between an insertion opening for receiving the terminal shoe and an access opening; a terminal screw having a screw head and a screw shank disposed in the interior of the terminal socket, the screw being actuatable in a longitudinal direction within the interior of the terminal socket between an open state and a clamped state, wherein a coupling is provided between the screw head and the insulating housing in the interior of the terminal socket as to enable actuation in the longitudinal direction and prevent the screw from tilting; a connection plate having a screw hole with interior threads for threadably engaging the terminal screw when in the clamped state; a retaining device preventing the terminal screw from being removed from the terminal socket when in the open state; a U-shaped busbar having a first leg and a second leg connected via a web, the busbar disposed in the housing, and wherein the first leg includes the connection plate; and a testing opening providing access to the web for at least one of testing and calibration, wherein the open state provides a gap allowing the terminal shoe to be inserted into the insertion opening, the clamped state provides the screw shank being engaged with the terminal shoe, and wherein access to the terminal screw is provided via the access opening of the terminal socket to allow for actuation of the terminal screw.