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A to Z of Cable Tray Wring System

If you are looking for or if you are in process of installing cable tray wiring system, better you read this article to know almost everything about cable tray wiring system.

What is a Cable Tray System?

Per the National Electrical Code, a cable tray system is "a unit or assembly of units or sections and associated fittings forming a rigid structural system used to securely fasten or support cables and raceways."

What does this mean?

• Cable trays support cable the way that roadway bridges support traffic.
• A bridge is a structure that provides safe passage for traffic across open spans.
• Cable tray is the bridge that allows for safe transport of wires across open spans.
• Therefore, think of cable tray as the structural component of a building's electrical system.

What types of Cable Tray are available?

1. Ladder
2. Solid Bottom
3. Trough
4. Channel
5. Wire Mesh
6. Single Rail

What materials / finishes are available for the various cable tray systems?

1. Steel
2. Aluminum
3. Fiber Reinforced Plastic

What types of cable trays are available, what configurations are available?

1. Straight sections are available to route cables in a horizontal or vertical plane.
2. Fittings are available to route cables in various directions in either the horizontal or vertical planes. Typical examples of fittings include elbows, tees, crosses, and risers. Each of these fittings are available in various radii and bend angles.
3. Covers are accessories and shouldn't be in here unless splices etc. are included.

After selecting the type of cable tray and configuration required, what support methods are available?

1. Trapeze Support (Single or Multi-tier)
2. Hanger rod clamps, "J" hangers
3. Center Hung Support
4. Wall Support
5. Under floor Support
6. Pipe stanchions or other structures

Each of these support methods are preferable in different applications. For instance, trapeze supports may be desired in an application where cables will be pulled through the cable tray. Center hung supports, on the other hand, are generally used when cables will be installed from the side of the cable tray. Center hung supports are especially useful when future cable additions are desired. Wall supports and under floor supports are useful when ceiling structure is not available or undesired. Outdoor installations are controlled by the structures available to support the cable tray.

Is it common practice to use cable trays in the vertical position?

It is common practice to use cable trays in the vertical position. I have many photos of such installations. There is no problem. Cables must be fastened securely.

 

Do they maintain their integrity during a 25 or 30 year life of a plant?

Yes, they do maintain their integrity. The only aging problem could be the tie wraps, especially for single conductor cables.

 

Is the percent filling of a vertical tray the same as a horizontal cable tray?

There are no differences between the cable fill requirements for vertical and horizontal cable tray installations.

 

Can mechanical utility piping or tubing containing water or compressed air be installed in cable trays with electrical cables?

No. Cable trays are a support system for electrical cables, power, signal, and communication and optical fiber cables.

 

What types of cables can be installed in Cable Tray systems?

They include:

• Power and Control Tray Cable
• Power Limited Tray Cable
• Optical Fiber Cables
• Fire Alarm Circuit Conductors
• Communication Cables
• Mineral Insulated (MI)Cable
• Metal Clad (MC) Cable

And other cables, including those specially approved for installation in cable trays. Medium voltage (type MV) and single conductor cables in sizes 1/0 and larger are permitted with some restrictions in Industrial Establishments where qualified persons service the installation.

 

Hope, all the information provided in this article will help you in deciding whether or not to g o for the cable tray wiring system.

 

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