Cable ladder systems and cable tray systems are designed for use as supports for cables and not as enclosures giving full mechanical protection. They are not intended to be used as ladders, walk ways or support for people as this can cause personal injury and also damage the system and any installed cables.
Ladder Cable Tray systems consists of two longitudinal side members connected by individual transverse members, and is designed for use as a power cable or control cable support system. Ladder and ventilated trays may have solid covers to protect cables from falling objects, dust, and water. Tray covers for use outdoors or in dusty locations may have a peaked shape to shed debris including dust, ice or snow. Lighter cable trays are more appropriate in situations where a great number of small cables are used, such as for telephone or computer network cables. These trays may be made of wire mesh, called "cable basket",or be designed in the form of a single central spine (rail) with ribs to support the cable on either side.
In the electrical wiring of buildings, a cable tray system is used to support insulated electrical cables used for power distribution, control, and communication.
Large power cables laid in the tray may require support blocks to maintain spacing between conductors, to prevent overheating of the wires. Smaller cables may be laid unsecured in horizontal trays, or secured with cable ties to the bottom of vertically mounted trays.
To maintain support of cables at changes of elevation or direction of a tray, a large number of specialized cable tray fittings are made compatible with each style and manufacturer. Horizontal elbows change direction of a tray in the same plane as the bottom of the tray and are made in 30, 45 and 90 degree forms; inside and outside elbows are for changes perpendicular to the tray bottom. These can be in various shapes including tees and crosses. Some manufacturers and types provide adjustable elbows, useful for field-fitting a tray around obstacles or around irregular shapes.
A cable ladder system comprises of a range of straight lengths as well as different shaped fittings designed to facilitate changing cabling directions or levels easily, without the need to modify any components. Ladders are generally considered to be the strongest products that are available to support cables, offering high load capabilities over long spans, and therefore are often specified to be installed on sites where the need to distribute high volumes of cables safely, reliably and quickly is of paramount importance to the project managers.