Wiring system design: Cable tray vs. conduit

 Wiring system design: Cable tray vs. conduit

Electric wiring must move from one place to the other in order to be functional. Distribution is an essential phase in the wiring system design. It allows power and impulse signals to reach their final destinations.

In the past, cables and wires were pulled through conduit. The patterns of numerous parallel conduit runs in plant environments (Fig. 1). Conduit remains the foundation of electrical power distribution.

Cable trays have been gaining popularity in industrial plants. Cable trays are used by approximately 85% of Canada's industrial plants instead of conduit. The percentage of industrial plants using cables trays in the U.S. is less, with just 50%. The U.S. is shifting towards cable tray use. While the U.S. market for data and communication cables has already accepted wire tray, contractors and power system engineers are still not fully accepting this trend. The electrical power segment is still relatively new to wire tray.

Cable tray

The National Electrical Code defines a cable tray as "a unit, or an assembly of units or segments and associated fittings that forms a rigid structural structure used to securely fasten cables and raceways."

Cable tray advantages include simplicity and flexibility in wiring system design as well as lower installation costs. Cable trays are flexible in plant environments where equipment is added, removed or moved. 2). Cable trays can be used in complex configurations by using a small set of tools. Although the cost of material procurement is lower for cable tray systems than for conduit systems, it is still less expensive than for conduit systems. Cable trays offer significant savings when compared to the labor cost of installing conduit.

Ladder -- offers solid side rail protection and system strength. It also features smooth radius fittings and a wide range of materials and finishes. Applications with long support spans of intermediate to high length are most commonly fitted with the Ladder Cable Tray.

Solid bottom -- Nonventilated continuous support for delicate cable with added protection in metallic and fiberglass. For nonplenum-rated cable, solid bottom metallic tray are available with solid metal covers. A solid bottom cable tray can be used in telecommunications or heat-generating applications that require short to intermediate support spans.

Trough -- Provides moderate ventilation with increased cable support frequency. With the bottom configuration providing support for every 4in, it provides cable support. The trough cable tray comes in both metal and non-metallic materials. It is typically used for moderate heat generation applications, with short to intermediate support spans.

Channel -- This is an economical option for supporting cable drops and branch cables from the backbone tray system. If conduit is not required, channel cable tray is for installations that require a small number of cable cables.

Wire mesh -- This is a field-adaptable support system that can be used on the job site, or in the field, primarily for low voltage wiring. Wire mesh tray is used primarily for fiber optic and telecom applications. Wire mesh tray systems typically consist of zinc-plated steel wire mesh.

Single rail -- This allows for faster system installation and allows cables to freely enter and exit the tray. Single-rail cable tray are used for low-voltage or power cable installations. They allow maximum cable freedom, side fill, speed, and installation speed. These aluminum systems are available in either single-hung or wall-mounted configurations with multiple tiers.

Cable tray configurations

Straight sections can be used for routing cables in a horizontal and vertical plane. Fittings allow cables to be routed in either the horizontal and vertical planes. Elbows, tees and crosses are all common fittings. These fittings can be ordered in different radii or bend angles. a review of the straight tray for th4fold