This system for building up electrified lines in the form of double-voltage exposed modules for supporting user appliances, particularly lighting lamps for interior environments, is formed from track pieces of standardized length along which conductors extend to form electrical lines, said track pieces being connectable together with the aid of interposable means including a prismatic box of square cross-section which is open at one of its ends to form various geometrical configuration suggested by aesthetic and/or functional requirements, and being combinable with supports for user appliances, particularly lamps of various types, along their entire length.

A ducting system comprising ducts of mainly U-shaped cross-section with bare hollow conductors fitted at the inner surfaces thereof, which conductors are accessible for corresponding contact pins of a contact element to be locked in arbitrary points on the open side of a duct, auxiliary parts being used for interconnecting such ducts and connecting a duct with a current supply. The improvement is that the conductors each consist of a continuous elastic metal strip bent into a mainly closed tube with oppositely bent outer rims, which conductors are retained in an insulating and non-rotatable manner in interior channels having a narrow access slot allowing a contact pin to be inserted through a slot into the narrow opening of the conductor in question between the outwardly bent outer rims, the adjacent bends of the conductor then being lateraly displaced so as to clamp the sides of the contact pin under spring tension and to make electrical contact therewith, interconnecting pins being used for interconnecting corresponding conductors of aligned ducts or a conductor of a duct and a corresponding conductor of an auxiliary part, these pins having a diameter which is larger than the smallest diameter of a hollow conductor in the unstressed state, so that such a pin, when inserted axially into the extremity of a conductor will be elastically clamped by inner wall portions of the conductor making electrical contact therewith.

An adaptor for connecting a luminaire to a track receptacle is disclosed. The track receptacle has retaining flanges along its bottom edges and an insulator assembly adjacent the top. The insulator assembly mounts parallel electrical conductors in the top of the track receptacle and also defines parallel guide channels. The adaptor includes a body having a lid. The lid includes retainers for mating with the retaining flanges. A pair of spring biased electrical contacts extend upwardly from a contact housing mounted in the body and extending through the lid. The housing includes a pair of guide members which are rotationally biased to an aligned position for insertion into the track receptacle.