Cable tray 2023 national standard

The 2023 cable tray standards include updates to NEC Article 690.31(C), NEMA VE1/VE2 guidelines, and IEC 61537:2023, covering conductor sizing, tray load ratings, and protective earth usage.NEC 2023 UpdatesThe 2023 National Electrical Code (NEC) introduced clarifications in Article 690.31(C) regarding cable trays, particularly for small conductors like PV wire and distributed generation (DG) cable on rooftops. Key updates include:Formal allowance for smaller conductors in cable trays.Guidance on ampacity calculations, number of conductors per tray, and tray width sizing.Instructions for layering or bundling conductors in certain installations.Updated correction factors for different installation methods to ensure safe current-carrying capacity .NEMA StandardsThe National Electrical Manufacturers Association (NEMA) provides two key standards:NEMA VE1: Specifies manufacturing requirements for metal cable trays (ladder, channel, wire mesh, solid bottom) and associated fittings, including load/span class designations. Harmonized with CSA C22.2 #126.1 for Canadian compliance .NEMA VE2: Provides installation guidelines for cable tray systems, covering shipping, handling, storage, and maintenance . Nonmetallic cable trays are covered under UL 568, which ensures safe application of fiberglass trays .IEC 61537:2023The International Electrotechnical Commission (IEC) released IEC 61537:2023, a technical revision of the 2006 edition. Key points include:Requirements and tests for cable tray and ladder systems for electrical and communication installations.New annexes covering use of trays as protective earth conductors.Updated corrosion classification with more granular categories.Focus on grouping cables and supporting electrical equipment, but excludes conduit, trunking, and ducting systems .Comparison and Practical ConsiderationsNEC/NEMA standards are widely used in the U.S., focusing on ampacity, tray sizing, and installation safety.IEC 61537:2023 is used internationally and emphasizes corrosion resistance, protective earth usage, and prescriptive thickness tables.When specifying cable trays, it is important to check manufacturer load data and ensure compliance with the applicable standard, as NEMA and IEC load ratings are not directly interchangeable .SummaryFor 2023, cable tray standards provide comprehensive guidance on:Conductor sizing and ampacity (NEC 690.31(C))Tray manufacturing and installation (NEMA VE1/VE2, UL 568)International compliance and protective earth usage (IEC 61537:2023)Material selection, corrosion, and load ratings for safe and code-compliant installations. These updates ensure that cable tray systems are safe, efficient, and compliant with both national and international electrical codes.