Cable Tray Materials
Metallic cable trays are readily available in aluminum, pregalvanized steel,
A fine print note has been added in the 2002 NEC® that references the National Electrical Manufacturers Association (NEMA) documents for further information on cable tray. These documents: NEMA
392.2. Definition. Cable Tray System.
This section states that cable tray is a rigid structural support system used to securely fasten or support cables and raceways. Cable trays are not raceways. Cable trays are mechanical supports just as strut systems are mechanical supports. NEC® Article 392 - Cable Trays is an article dedicated to a type of mechanical support. It is very important that the personnel involved with engineering and installing cable tray utilize it as a mechanical support system and not attempt to utilize it as a raceway system. There are items in the NEC® that apply to raceways and not to cable tray. There are also items in the NEC® that apply to cable tray and not to raceways. These differences will be covered at the appropriate locations in this manual.
392.3. Uses Permitted. Cable tray installations shall not be limited to industrial establishments.
The text in Section 392.3 clearly states that cable tray may be used in
For clarity, the NEC® now lists all types of circuits to explicitly permit their use in cable trays. These circuit types include: services, feeders, branch circuits, communication circuits, control circuits, and signaling circuits.
Cooper B-Line, Inc
The 2002 NEC® also added a new requirement that where cables in tray are exposed to the direct rays of the sun, they shall be identified as sunlight resistant for all occupancies, not just industrial.
392.3.Uses Permitted. (A) Wiring Methods.
This section identifies the 300 & 600 volt multiconductor cables that may be supported by cable tray. The "Uses Permitted" or "Uses Not Permitted" sections in the appropriate NEC® cable articles provide the details as to where that cable type may be used. Where the cable type may be used, cable tray may be installed to support it except as per Section 392.4 which states that cable trays shall not be installed in hoistways or where subject to severe physical damage. Where not subject to severe physical damage, cable tray may be used in any hazardous (classified) area to support the appropriate cable types in accordance with the installation requirements of the various Articles that make up NEC® Chapter 5 or in any
It should be noted that Section 300.8 of the NEC® states that cable trays containing electric conductors cannot contain any other service that is not electrical. This includes any pipe or tube containing steam, water, air, gas or drainage.
For commercial and industrial cable tray wiring systems: Type ITC, Type MC, Type TC, and Type PLTC multiconductor cables are the most commonly used cables. Type MI and
Type MI Cable:
Cable Tray Manual
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