The types of cables, allowed in cable trays, and the wiring methods permitted in cable trays can be found in NEC Section 392. This Section also lists various corresponding NEC Articles which describes the conditions of use, and installation requirements for a. us-trations without notice. All illustrations, descriptions and technical information included in this document are provided as indications and can cable trays are equivalent. The mechanical and electrical characteristics, tests, certifications, overall quality management, recommendations mentioned. Southwire SIMpull ® THHN/THWN-2 copper conductors are primarily used in conduit and cable trays for services, feeders, and branch circuits in commercial or industrial applications as specified in the National Electrical Code® and other applicable codes and standards. Voltage for all applications is. maintain spacing or to keep cables in place when the tray is ect the minimum bend ra-dius for cables as they exit the bottom of the cable tray. THHN applications are suitable for use in dry locations only at temperatures not to exceed 90°C.