We are installing a new machine which has next to it a 2-ton jib crane that rotates 360 degrees. The operators have a need for 120 and 480/3 electrical under the swing of this jib so obviously cord drops are out of the question. I didn't want a bunch of drop cords, expecially 480, laying on the floor so I built a steel riser (for lack of a better word) that is set into the floor near the base of the jib.
I have buried conduit in the concrete feeding this riser, four in total. One each from the 480/3 and 120 panel, and two from the machine. All three, although different sizes, are configured the same: the stubs and elbows in the concrete are RGS, the laterals are PVC. Do I have to have to use bonding bushings on the riser end of all four conduits or is one enough with locknuts only on the others? And secondly, do I have to use bonding bushings on the other end at all?
I have buried conduit in the concrete feeding this riser, four in total. One each from the 480/3 and 120 panel, and two from the machine. All three, although different sizes, are configured the same: the stubs and elbows in the concrete are RGS, the laterals are PVC. Do I have to have to use bonding bushings on the riser end of all four conduits or is one enough with locknuts only on the others? And secondly, do I have to use bonding bushings on the other end at all?