2 Do horizontal and vertical trays need to be different sizes? Cable trays vary in size in order to accommodate varying numbers of wires. International projects are most often made in widths of between 50mm and 900mm and depths of between 50mm and 150mm. In practice, cable tray dimensions are a system of interrelated. Selecting the right cable tray size is critical for electrical safety, system efficiency, and cost control. Here in the UK, standard widths run from a slim 50mm for a handful of data runs right up to 900mm or more for the heavy-duty. When choosing the size of cable tray, it is a tradeoff between the existing volume of cable and the future volume of cable. A tray that is too small will overheat and physically damage, and too large tray will drain the project budget. It is grounded on 40 years of experience in the manufacturing. us-trations without notice.