For horizontal sections where cable trays are laid out in a straight line, the typical support span (distance between supports) should range from 1. This range allows for easy access and efficient maintenance. It also helps reduce the risk of. Although BS 7671 touches on the subject of cable supports, it does not detail specifically what these support distances should be. 8 (Other Mechanical Stresses (AJ)) in that document provides requirements for cable support. Begin by reviewing the approved shop drawing, which includes essential details. maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray.