The diameter of a circle is the total width across the center and the radius is the distance from the center to the circumference. The normal recommendation for fiber optic cable is the minimum bend radius under tension during pulling is 20 times the diameter of the cable (d). When bent too sharply, helical metal tapes can eparate. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. Cable trays play a vital role in supporting electrical cables and wires in commercial, industrial, and utility installations. Cables are often bent around a curve in conduits or underground ducts.