National Standard Number for Steel Cable Trays

Steel cable trays in the U. S. are primarily governed by NEMA VE 1, NEMA VE 2, UL 568, and the National Electrical Code (NEC), with international guidance from IEC 61537. Key U.

S. StandardsNEMA VE 1 – Metal Cable Tray Systems This standard specifies the manufacturing requirements for steel cable trays, including ladder, ventilated trough, channel, solid bottom, and wire mesh types, along with associated fittings. It defines load/span class designations, material specifications, and structural performance criteria to ensure safe support of power and control cables in accordance with the NEC.

V

E 1 is harmonized with CSA C22. 2 No. 126.

1 for Canadian applications and is periodically updated to reflect technological advances.

NEMA V

E 2 – Installation Guidelines VE 2 provides practical guidance for the installation, handling, storage, and maintenance of metal cable tray systems. It addresses proper support spacing, bending radius for cables, and environmental considerations such as corrosion protection.

V

E 2 complements VE 1 by translating manufacturing standards into field installation practices.

U

L 568 – Performance Requirements Although primarily for fiberglass trays, UL 568 establishes safety and performance testing protocols that can inform steel tray design, particularly regarding load-bearing and fire safety considerations. National Electrical Code (NEC, NFPA 70) The NEC governs the installation and electrical safety of cable tray systems. Article 392 covers ladder, ventilated trough, channel, and solid bottom trays, specifying ampacity, grounding, and conductor support requirements.

Compliance with NEC ensures that steel cable trays meet both structural and electrical safety standards. International StandardIEC 61537: 2023 This standard specifies requirements and tests for cable tray and ladder systems used in electrical and communication installations. It includes guidance on load capacity, grouping of cables, and protective earth conductor use, providing a global benchmark for steel cable tray systems.

Material and Corrosion Considerations

Steel cable trays are typically manufactured from pre-galvanized, hot-dip galvanized, or stainless steel (AISI 316L) to ensure corrosion resistance and mechanical strength. Stainless steel may include chromium and molybdenum to enhance resistance to chlorides and other corrosive environments. Material selection depends on environmental exposure, load requirements, and installation location.

Summary

For compliance and safety, engineers and contractors should reference: NEMA VE 1 for manufacturing and load/span requirementsNEMA VE 2 for installation and maintenance practicesNEC Article 392 for electrical safety and conductor supportIEC 61537 for international design and testing guidanceUL 568 for performance testing considerations These standards collectively ensure that steel cable trays are structurally sound, electrically safe, and suitable for their intended environment.