Where cable trays support individual conductors or multiconductor cables and where the conductors or multiconductor cables pass from one cable tray to another, or from a cable tray to raceway (s) or from a cable tray to equipment where the conductors are terminated, the. Where cable trays support individual conductors or multiconductor cables and where the conductors or multiconductor cables pass from one cable tray to another, or from a cable tray to raceway (s) or from a cable tray to equipment where the conductors are terminated, the. Size conductors installed in cable tray with NEC 392, NEC 310. 16, tray fill, ampacity adjustment, voltage-drop checks, grounding, and IEC design cross-checks. Use NEC 392 for tray rules, but still size conductors from NEC 310. Tray fill, spacing, ambient temperature, and sun exposure. NEC Article 392 governs cable tray installations, covering tray types, fill limits, cable types permitted, and ampacity adjustments. The fill rules differ significantly between single-conductor cables and multiconductor cables, and between ladder tray and solid-bottom tray. Optimizes jobsite installations with faster quotes and direct wire requests. The selected values are used to populate the two lower tables that have standard values. Some have only been evaluated to secure or position a cable.