392 – Cable Trays
392.10 – Limitations of Single Conductor Applications in Cable Tray Systems
Change at a Glance:
Revision provides clarity relative to the limitations of single conductor applications in cable tray systems.
392.10 Uses Permitted. (Cable Trays)
Cable tray shall be permitted to be used as a support system for wiring methods containing service conductors, feeders, branch circuits, communications circuits, control circuits, and signaling circuits. Single insulated conductors shall be permitted in cable tray only when installed in accordance with 392.10(B)(1). Cable tray installations shall not be limited to industrial establishments. Where exposed to direct rays of the sun, insulated conductors and jacketed cables shall be identified as being sunlight resistant. Cable trays and their associated fittings shall be identified for the intended use.
392.30(B)(4) – Securing and Supporting (Cable Trays)
Change at a Glance:
Cable ties used to secure and support conductors and cables in a cable tray are an acceptable means of securement when identified for securement and support in a cable tray.
392.30 Securing and Supporting (Cable Trays)
(A) Cable Trays. Cable trays shall be supported at intervals in accordance with the installation instructions.
(B) Cables and Conductors. Cables and conductors shall be secured to and supported by the cable tray system in accordance with (1), (2), and (3), and (4) as applicable:
(1) In other than horizontal runs, the cables shall be fastened securely to transverse members of the cable runs tray.
(2) Supports shall be provided to prevent stress on cables where they enter raceways from cable tray systems.
(3) The system shall provide for the support of cables and raceway wiring methods in accordance with their corresponding articles. Where cable trays support individual conductors or multiconductor cables and where the conductors or multiconductor cables 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 raceway(s) or the equipment shall not exceed 1.8 m (6 ft). The conductors shall be secured to the cable tray(s) at the transition, and they shall be protected, by guarding or by location, from physical damage.
(4) Cable ties shall be listed and identified for the application and for securement and support.
392.44 – Expansion Splice Plates
Change at a Glance:
New section added for expansion splice plates to address thermal expansion and contraction due to temperature variations for cable trays.
392.44 Expansion Splice Plates.
Expansion splice plates for cable trays shall be provided where necessary to compensate for thermal expansion and contraction.
392.46 – Bushed Conduit and Tubing. (Cable Trays)
Change at a Glance:
Individual conductors and multi-conductor cables transitioning from a cable tray to raceways or openings associated with flanges entering enclosures is a compliant application.
392.46 Bushed Conduit and Tubing. (Cable Trays)
A box shall not be required where cables or conductors are installed in bushed conduit and tubing used for support or for protection against physical damage or where conductors or cables transition to a raceway wiring method from the cable tray. Conductors shall be permitted to enter equipment in accordance with 392.46(A) or (B).
(A) Through Bushed Conduit or Tubing. Individual conductors or multiconductor cables with entirely nonmetallic sheaths shall be permitted to enter enclosures where they are terminated through nonflexible bushed conduit or tubing installed for their protection provided they are secured at the point of transition from the cable tray and the conduit or tubing is sealed at the outer end using an approved means so as to prevent debris from entering the equipment through the conduit or tubing.
(B) Flanged Connections. Individual conductors or multiconductor cables with entirely nonmetallic sheaths shall be permitted to enter enclosures through openings associated with flanges from cable trays where the cable tray is attached to the flange and the flange is mounted directly to the equipment. The openings shall be made such that the conductors are protected from abrasion and the opening shall be sealed or covered to prevent debris from entering the enclosure through the opening.
Informational Note: One method of preventing debris from entering the enclosure is to seal the outer end of the raceway or the opening with duct seal.