(57) A supply connector for an electrical distribution system of the continuous outlet type having a track in the form of a channel (1) housing longitudinally extending conductors (4) is adapted to be inserted through the mouth of the channel and accommodated entirely within the channel. The connector includes longitudinally extending contacts (15) adjustable between retracted positions within the connector housing and operative positions projecting from the housing by a cam member (20) which is slidable in the housing and driven by a rack and pinion mechanism (29, 30), the pinion being formed as a toothed quadrant fast with an operating lever (31).