NEC Article 392 outlines the key rules for installing and maintaining industrial cable tray systems. These systems, made from metal or plastic, are open structures designed to support electrical conductors, ensuring proper organization and safety. Here's what you need to know:The primary rulebook used in the safe use of cable trays is NEC Article 392. You should consider it as a series of instructions that make the buildings resistant to. It is the first joint effort of NEMA and CSA International to put in one place standards for metal trays per both NEMA and CSA methods. Historically, the NEC has allowed cable trays, but has lacked specific guidelines for sizing conductors and using smaller. Cable tray standards include the following: NEC: The National Electrical Code. CSA: Canadian Standards Association.