IEC 61537:2023 specifies requirements and tests for cable tray systems and cable ladder systems intended for the support and accommodation of cables and possibly other electrical equipment in electrical and/or communication systems installations. Covers construction and test requirements for. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. Historically, the NEC has allowed cable trays, but has lacked specific guidelines for sizing conductors and using smaller. The B-Line series Cable Tray Manual was produced by our technical staff.