Views: 0 Author: Site Editor Publish Time: 2026-09-30 Origin: Site
Quick answer: NEMA VE 1 and IEC 61537 are the two main performance standards for metal cable tray. NEMA VE 1 is used mainly in North America, IEC 61537 (EN 61537) in Europe and most other markets. UL 568 is a different kind of standard: it covers non-metallic cable tray, such as fiberglass (FRP). The three are not interchangeable, and their load ratings cannot be compared directly.
A cable tray carries cables for decades, often above people, equipment and other services. A standard defines how the tray is tested, how its load rating is declared, and what safety margin sits behind that rating. When a tender says "cable tray to NEMA VE 1" or "compliant with IEC 61537", it is telling you which test method and which rating language to expect on the datasheet.
NEMA VE 1 is published by the National Electrical Manufacturers Association (USA) and covers metal cable tray: ladder, ventilated trough, solid-bottom and similar types in steel, stainless steel and aluminum. Its companion, NEMA VE 2, covers installation.
Load classes combine a support span and a load letter. The number is the span in feet (8, 12, 16 or 20 ft). The letter is the working load: A = 50 lb/ft, B = 75 lb/ft, C = 100 lb/ft.
Example: Class 12B means the tray can carry 75 lb/ft over a 12 ft span (about 1,095 N/m over 3.66 m).
Testing: the tray is tested as a simple beam under a uniformly distributed load, with a safety factor of 1.5 applied to the rated load.
Where it applies: projects in the USA, and many projects in Latin America and the Middle East that follow US specifications. In the US, metal tray is also connected to NEC Article 392 and to third-party listing (e.g. UL or ETL). In Canada the equivalent product standard is CSA C22.2 No. 126.1.
IEC 61537 is the international standard for cable tray and cable ladder systems, adopted in Europe as EN 61537. Unlike NEMA VE 1, it covers both metallic and non-metallic systems.
Rating language: the manufacturer declares a Safe Working Load (SWL) in N/m (or kN/m) for a stated support span in metres, for example 1,500 N/m at 2.0 m.
Testing: the tray is loaded uniformly and deflection is measured at the SWL. The standard also specifies a higher proof load, with a safety factor of 1.7 on the SWL.
Beyond load: it also covers classification of corrosion protection, electrical continuity, temperature range, fire behavior, and marking.
Where it applies: Europe, the Middle East, Africa, Southeast Asia, Australia and most export markets.
UL 568 is a binational standard (harmonized with CSA C22.2 No. 126.2) for non-metallic cable trays and fittings used under the National Electrical Code (NEC) and the Canadian Electrical Code. In practice this means mainly fiberglass-reinforced plastic (FRP) tray.
It uses a class designation similar to NEMA VE 1: span in feet plus a load letter (A, B or C).
It is chosen where corrosion resistance or non-conductivity matters: chemical plants, wastewater, offshore, coastal sites.
It does not apply to steel, stainless steel or aluminum tray. Those are covered by NEMA VE 1 / CSA C22.2 No. 126.1 in North America.
NEMA VE 1 | IEC 61537 | UL 568 | |
|---|---|---|---|
Material scope | Metal | Metal and non-metal | Non-metal (e.g. FRP) |
Main region | North America | Europe and international | North America |
Rating format | Class, e.g. 12B (span in ft + load letter) | SWL in N/m at a stated span in m | Class, e.g. 20C |
Safety factor in test | 1.5 | 1.7 | See standard |
Units | lb/ft, ft | N/m, m | lb/ft, ft |
Related code | NEC Art. 392, CSA C22.2 No. 126.1 | EN 61537, national wiring rules | NEC, CEC, CSA C22.2 No. 126.2 |
Not directly. A "500 N/m" IEC rating and a "Class 8A" NEMA rating are stated in different units, at different spans, and proven with different safety factors and test procedures. Converting units is easy (1 lb/ft ≈ 14.6 N/m, 1 ft = 0.3048 m), but the test basis still differs. When you compare suppliers, check three things: the standard named, the support span and the safety factor behind the number.
Project in the USA or Canada, metal tray: NEMA VE 1, plus the third-party listing your authority having jurisdiction requires.
Project in Europe, the Middle East, Africa, Asia or Australia, metal tray: IEC 61537 / EN 61537, usually together with CE marking requirements where applicable.
Corrosive or non-conductive environment in North America: UL 568 non-metallic tray.
Export project with a mixed specification: ask the engineer which standard governs the tender, and request test data at the span used on site.
Our cable trays are supplied under the WA-CT model system (for example WA-CT-300100-1.2, meaning 300 × 100 mm, 1.2 mm thickness). Load data for our perforated cable tray is published at a 1.5 m support span, from 50 × 50 mm up to 1200 × 200 mm, with safe working loads from 500 to 2,600 N/m. See our guide to Cable Tray Load Capacity & Support Span for how to read these numbers, and our news on CE and IEC 61537 certification. If your project specifies a different span or a different standard, send us your drawings and we will confirm what we can supply.
Is UL 568 for steel cable tray?
No. UL 568 covers non-metallic cable tray. Metal tray in North America is covered by NEMA VE 1 and CSA C22.2 No. 126.1.
What is the difference between NEMA VE 1 and IEC 61537?
NEMA VE 1 uses span-and-letter load classes (lb/ft, ft) with a 1.5 safety factor and is mainly used in North America. IEC 61537 uses a declared SWL in N/m at a stated span with a 1.7 proof factor and is used across Europe and most export markets.
Does IEC 61537 apply to cable ladder as well?
Yes. The standard covers both cable tray systems and cable ladder systems.
Can I use NEMA-rated tray on an IEC project?
Only if the specification allows it. Ask the consultant or authority in charge, and request test data at the span used on site.
Where is the load rating of my tray stated?
On the manufacturer's datasheet and test report. It should name the standard, the span and the load.
Need help choosing? Send us your project specification and required load, and our team will reply with a recommendation.
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