The typical radius is 24 inches. Fittings are also available for 30°, 45°, 60° and 90° angles. It may be necessary to add supports to the tray at these points. Understanding the correct cable tray bending radius helps engineers, electricians, and installers maintain safe cable routing and comply with IEC, NEC, and manufacturer standards. Estimate safe cable tray inside and outside. Enter bend centerline radius: Input the catalog centerline radius (CLR) of the elbow. Enter offset parameters: If calculating an offset bend, enter the structural horizontal distance (run) and vertical/lateral offset depth (rise) to calculate. Made or assembled in Canada. What Regulations Govern Power Cable.