A connection bar comprising a body made of conductive material extending along a longitudinal axis, with first and second parallel longitudinal external surfaces (51, 52) and third and fourth longitudinal external surfaces (53, 54) perpendicular to said first and second external surfaces (51, 52), said body being perforated with a plurality of orifices delimiting connection housings which extend along transverse axes parallel to one another and perpendicular to the longitudinal axis and which open onto at least one of the first and second longitudinal external surfaces (51, 52), said body of the connection bar comprising, in correspondence with each connection housing, a threaded conduit, with a central axis perpendicular to the longitudinal and transverse axes, one end of which opens into said connection housing and the other end of which opens onto the third longitudinal external surface, the connection bar being equipped, instead of a pre-determined connection housing, with a connection cage made of conductive material that U-shaped with a base and two parallel branches (62, 63) which internally delimit a connection zone accessible via at least one first opening provided in a first of said branches, both branches (62, 63) being placed opposite said first and second longitudinal external surfaces (51, 52) of the body and extending in directions substantially parallel to said central axis, beyond the third longitudinal external surface, characterised in that both branches (62, 63) of the connection cage comprise, at their free ends, flanges (62A, 63A) which overlap opposite said third longitudinal external surface of the body, said flanges (62A, 63A) being perforated with threaded holes (62B, 63B) whose axes are aligned with the central axis of the threaded conduit opening into said pre-determined connection housing, and receiving a clamping screw screwed into said threaded holes (62B, 63B) and into said threaded conduit, a free end of the clamping screw abutting against an internal surface of said pre-determined connection housing, such that, during screwing, the base of the connection cage is moved in the direction of the fourth longitudinal external surface of the body of the connection bar. said body of the connection bar comprising, in correspondence with each connection housing, a threaded conduit, with a central axis perpendicular to the longitudinal and transverse axes, one end of which opens into said connection housing and the other end of which opens onto the third longitudinal external surface, the connection bar being equipped, instead of a pre-determined connection housing, with a connection cage made of conductive material that U-shaped with a base and two parallel branches (62, 63) which internally delimit a connection zone accessible via at least one first opening provided in a first of said branches, both branches (62, 63) being placed opposite said first and second longitudinal external surfaces (51, 52) of the body and extending in directions substantially parallel to said central axis, beyond the third longitudinal external surface, characterised in that both branches (62, 63) of the connection cage comprise, at their free ends, flanges (62A, 63A) which overlap opposite said third longitudinal external surface of the body, said flanges (62A, 63A) being perforated with threaded holes (62B, 63B) whose axes are aligned with the central axis of the threaded conduit opening into said pre-determined connection housing, and receiving a clamping screw screwed into said threaded holes (62B, 63B) and into said threaded conduit, a free end of the clamping screw abutting against an internal surface of said pre-determined connection housing, such that, during screwing, the base of the connection cage is moved in the direction of the fourth longitudinal external surface of the body of the connection bar.