Specification notes
Cable tray load classes: NEMA VE 1 and IEC 61537 explained
Alainz Technical Team
A cable tray's structural rating is not a single number. Two systems dominate specifications: NEMA VE 1 (a load/span class expressed like a working load at a support span) and IEC 61537 (which classifies both the safe working load at a rated support distance and a corrosion-resistance class).
Load, span and deflection
A meaningful load statement always pairs a load with a support span and a deflection limit (for example 1/100 of the span). A tray rated at a high load over a short span is not equivalent to the same load over a longer span. Read the class, the span and the deflection together.
| System | What it classifies | Reads like |
|---|---|---|
| NEMA VE 1 | Working load at a support span | Class 12C / 16C at 8 ft span |
| IEC 61537 | Safe working load at rated support distance | SWL at 2 m support distance |
| Deflection | Stiffness under load | 1/100 of span |
Corrosion class and coating thickness
Where the environment is corrosive, the finish carries its own classification: IEC 61537 corrosion classes and a stated coating thickness in microns (µm) for galvanised finishes, or a stainless grade (SS304/SS316) for aggressive environments. A load class without a finish class is only half the specification.
General reference. Confirm ratings against the manufacturer's tested data for the exact section, support and finish specified.