Abstract: A recessed light fixture adapted to be installed in a hole in a ceiling panel having an exposed lower face and an opposite upper face has a frame bearing on the front face and engaged upward through the hole in the panel and a reflector mounted in the frame generally above the panel. A screw extending along an axis transverse to the panel is axially fixed in the frame above the panel, rotatable about the axis, and has an external screwthread. A retaining pawl is pivotal on the screw above the panel between an outer position projecting outward past the frame and an inner position and is displaceable axially along the screw downward toward the panel and upward away from the panel. A spring engaged between the pawl and the screw couples the pawl to the screw and is positioned to permit the pawl to move axially only downwardly relative to the screw. A cam on the frame forces the pawl into the outer position on downward axial displacement toward the panel.

Abstract: A bus bar with three phase conductors and one neutral conductor is engageable by an adapter in the shape of an elongate plug designed to connect an external circuit across the neutral conductor and a selected phase conductor. The adapter housing contains two parallel shafts A, B each carrying a resilient contact blade, these blades being retracted into the housing in a disengagement position and being extendible by rotation of the respective shaft through 90.degree.. A locking slide between the two shafts prevents rotation of shaft B until shaft A has been rotated to engage its blade with the neutral conductor whereupon shaft B may be rotated, in one of two axial positions, to bring the other blade into contact with the selected phase conductor whereby shaft A is locked in its engagement position. Shaft A also carries tongue-shaped detents which in its engagement position enter grooves in the bus bar to prevent untimely withdrawal of the adapter.