Abstract: A guide for flexible power lines connecting a power supply to a moving device includes a plurality of similar rectangular tubular duct elements mounted with adjacent elements telescoped into each other and pivotally connected to form a beam support in the linear direction and a curved support between the beam supports. Each element is a cast element of a suitable metal or other material having relatively heavy walls. The side walls include offset planar wall interconnected by transverse interior stop walls which are angularly oriented and shaped. The stop walls and the outer side wall end edges of the adjacent element are similarly shaped with first and second opposed wall portions. The first wall portion of the side walls abutt in the beam position and the second wall portions are spaced by the maximum pivotal movement.