Horizontal deviation: ≤2mm per meter. Must be level, plumb, and securely mounted on supports. Use dedicated splice plates and. Calculate horizontal, vertical, or compound cable tray offsets based on bend angle, offset distance, and available installation space. This guide covers the critical steps, from selecting the right electrical cable tray and performing accurate cable fill. This publication is intended as a practical guide for the proper and safe* installation of cable ladder systems, cable tray systems, channel support systems and associated supports. The system designer (engineer) who has access.