For cables larger than 4/0 AWG, cables are installed in a single layer (no stacking) and the sum of cable diameters must not exceed the tray width. For cables 4/0 AWG and smaller, the maximum fill is based on cross-sectional area, and cables may be stacked. For solid-bottom tray: The maximum fill. Below are the key principles to guide the layout of E&I cable trays, focusing on practical, safety, and efficiency aspects. Separation of Electrical and Instrumentation Cables Electrical on Top, Instrumentation Below: Typically, electrical trays are positioned above instrumentation trays. It instructs us on how to construct them, where to locate them, and how to stuff them with wires without using too much. 2 of the 2002 National Electrical Code (NEC), is a unit or assembly of units (commonly called sections) and the associated fittings that form a structural system used to securely fasten or support cables and raceways. 3 covers uses of cable trays.
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