• 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.

• The National Electrical Code publishes the standards for all types of electrical applications. Articles 318, 250, and 800 cover various aspects of cable tray systems.


• NEMA, (National Electrical Manufacturers Association), is an association comprised of the major cable tray manufacturers in the industry. This committee has published three documents to date: NEMA VE1, FG1 and VE2.


• NEMA VE1 covers general cable tray definitions, manufacturing standards, performance standards, test standards, and application information.


• NEMA FG1 addresses the standards for fiberglass cable tray systems.


• NEMA VE2 is a cable tray installation guideline which covers receiving and unloading material, storage of material, and general installation practices.

• Plain: hot rolled pickled and oiled steel per ASTM A569 (Commercial Quality) or A570 (Structural Quality)


• Pre-Galvanized: mill galvanized steel per ASTM A653 CS (Commercial) or SS (Structural) G90


• Hot Dip Galvanized after Fabrication: plain steel which is hot dipped after fabrication per ASTM A123.


• Stainless Steel: type 304 or 316L fully annealed stainless steel

• Polyester and Vinyl Ester resin systems available


• Meet ASTM E-84 smoke density rating; Polyester 680, Vinyl Ester 1025


• Class 1 Flame Rating and self-extinguishing requirements of ASTM D-635.

• Straight sections are available to route cables in a horizontal or vertical plane.


• 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 is available in various radii and bends angles.


• Covers are accessories and shouldn't be in here unless splices etc. are included.

Each of these support methods is 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.

Before selecting the type of cable tray, cable tray configuration(s), and support method desired, what additional information do I need to supply to the cable tray manufacturer for them to best understand and satisfy my needs?

• Supports available affect the length and strength requirements


• Environmental loads, ice, wind, snow, and possibly seismic


• Corrosion requirements affect the materials and finishes


• Classified hazardous locations affect the cable types acceptable

• Support locations available affect the length and strength of the system


• Industrial installation may require a 200 lb. Concentrated Load


• Commercial or institutional installation may make system appearance, system weight, and space available important factors


• Environmental air handling area may affect cable types, cable tray material, or cable tray type and need for covers


• Classified hazardous locations affect the cable types acceptable

• NEC cable fill requirements dictate size, width and depth, of system


• Cable support requirement may control bottom type


• Largest bending radius of cable controls fitting radius


• Total of cable weight determines load to support

• Cable entry / exit freedom


• Design partially full or an expandable system


• Support type to allow for needs