Abstract: A trenchduct (10) having an adjustable lid-supporting means (30, 40), the trenchduct (10) having either a bottom (14) or bottomless. The construction consists of metal side walls (12) each having an outward extending flange (18), adjuster bolts (22) mounted vertically upon the horizontally extending flanges (18), and galvanized steel Z-bar side members (30) having threaded openings (37) receiving the adjuster bolts (22) to support the Z-bar side members (30) in abutting relationship with vertical members (16) of the side walls (12). Aluminum side member extrusions (40) having diagonally opposed longitudinally extending slots (42, 43) are positioned upon and secured to the inwardly projecting flanges (34) of the Z-bar side members (30).

Abstract: A subfloor trenchduct (10) construction in which the side wall members (14, 16) and lid-supporting means (37) are constructed of galvanized steel in order to provide a reduced cross section for the component members and thereby maximizing the availability of internal space within the trenchduct (10) for electric service. The galvanized steel construction obviates larger cross sections previously employed in utilization of aluminum components which detracted from the effective use of internal space of the duct, and the aluminum components required protective coating since aluminum, when exposed to alkaline concrete, experiences deterioration of the components. The lid-supporting means (37) is made vertically adjustable relative to floor level so that prior to pouring of the concrete (66) the lid (30) is accurately located in relation to the floor.