Cable Tray "Thickness-Based Selection" Officially Obsolete — What Should Procurement Focus on Under the New Specification?

The first habit was that "negative tolerance" gained room to maneuver. When "nominal thickness 1.5 mm" became the common wording in contracts, non-compliant products had leeway: nominal 1.5 mm with actual material of 1.2 mm or even less was the underlying logic of many low-price quotations. This reduction is not simply "a little less thickness" — when a tray designed with a 1.5 mm wall thickness actually arrives at 1.2 mm, the section modulus drops by about 20%, and the actual load-bearing capacity decays by 15%–20%. After cables are installed, sagging and deformation of the tray are often discovered only after power is connected.

The second habit was treating thickness as the sole variable of load-bearing capacity. The logic behind the new specification revision points precisely to this: the load-bearing capacity of a cable tray has never been determined by plate thickness alone. Material grade, side height dimensions, whether reinforcing ribs are present, ladder rung arrangement, support and hanger span, and even the strength matching of connectors all change the final load-bearing performance. The same 1.5 mm plate used in a 200 mm-wide tray versus an 800 mm-wide tray produces completely different results; for the same specification, a 2-meter span and a 3-meter span are also two different things. In the past, using "minimum thickness" and "load class" as the criteria had the advantage of being simple and intuitive, but the disadvantage of being prone to one-size-fits-all judgments — a thick plate may still sag because of an unreasonable structural configuration, and blindly increasing thickness to pass inspection does not necessarily bring a synchronous improvement in load-bearing efficiency.