Abstract: Electrical current rail 1, which may function as collector rail for power distribution, houses phase conductors 35, 36 and zero-conductor 37, with which adaptor 2 is intended to come into contact via plugs (86, 98), which are connected to a respective phase conductor plug and zero-conductor plug (not shown) intended to provide electrical connection with said adapter 2. Said phase conductors 35, 36 are provided in the interior space 16 behind the front 7, 8 of the rail and are accessible only in a direction from the inside of the rear side 4 of the rail. The front 7, 8 is divided by an opening 11 for reception of an insertion part 49, 50 of the adapter 2 provided with a contact beam 78, which is both pivotable and movable backwards and forwards into contact with said phase conductors and out of contact with the same by means, e.g. screw 69, accessible on the front of the adapter 2.