Abstract: A modular conduit system is provided which includes at least one longitudinally extending shell component including an interior wall and an exterior wall, a first longitudinally extending edge, a second opposed longitudinally extending edge, an engagement tab located adjacent the first longitudinal edge, an engagement slot located adjacent the second longitudinally extending edge, the engagement slot having an enlarged portion and a narrow portion, the enlarged portion configured to receive an engagement tab from another longitudinally extending shell, the narrow portion configured to interfere with removal of the tab in a direction transverse to the slot. The longitudinally extending shells are combinable to form a conduit member which are themselves combinable to form a longitudinally extending array of conduit members. Swiveling elbow joints may be inserted between conduit members to provide changes in direction.