Where cable trays support individual conductors and where the conductors pass from one cable tray to another, or from a cable tray to raceway (s) or from a cable tray to equipment where the conductors are terminated, the distance between the cable trays or between the cable tray and the. Where cable trays support individual conductors and where the conductors pass from one cable tray to another, or from a cable tray to raceway (s) or from a cable tray to equipment where the conductors are terminated, the distance between the cable trays or between the cable tray and the. 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. Clause 522-08-04 Where conductors or cables are not supported. Cables and conductors shall be secured to and supported by the cable tray system in accordance with (1), (2) and (3) as applicable: (1) In other than horizontal runs, the cables shall be fastened securely to transverse members of the cable runs. (2) Supports shall be provided to prevent stress on. The B-Line series Cable Tray Manual was produced by our technical staff. The following pages address the 2014 National Electrical Code® requirements for cable tray systems as well as design. Center Supported Cable Tray (B-Line Cent-R-Rail System) The standard lengths for cable trays are 10, 12, 20 and 24 feet (consult B-Line for the availability of nonstandard cable tray lengths). Section 26 05 26 - Grounding and Bonding for Electrical Systems. List. Cable trays can be used as a support system for various wiring methods, including service conductors, feeders, branch circuits, communications circuits, control circuits, and signaling circuits (392.