For ladder cable trays supporting large power cables, 9 inch or wider rung spacings should be selected. IEC 61537 covers cable tray and cable ladder systems for the support and accommodation of cables, while NEC Article 392 governs cable. Cable tray is the preferred wiring method for industrial facilities, data centers, and large commercial buildings where routing dozens or hundreds of cables through individual conduits would be impractical and expensive. NEC Article 392 governs cable tray installations, covering tray types, fill. National Electrical Code (NEC) specifies the capacities of cables rated at 2000 volts or less in cable trays.
