Use NEC 392 for tray rules, but still size conductors from NEC 310. 16, tray fill, ampacity adjustment, voltage-drop checks, grounding, and IEC design cross-checks. Tray fill, spacing, ambient temperature, and sun exposure. A properly sized tray cable ensures reliable operation, extends the lifespan of your wiring system and meets NEC, UL and CSA standards. For the installation of single conductor cables sized 1/0 AWG to 4/0 AWG in industrial establishments, the NEC specifies the maximum allowable rung spacing for the cable. The primary rulebook used in the safe use of cable trays is NEC Article 392. This is a description of how to select, install, and support these metal or plastic frames, on which electrical wires are installed.
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