Free cable tray fill calculator built by licensed low-voltage contractors who pull cable every day. This tool covers conduit fill for Cat6 and Cat6A cables, fire-rated sleeve capacity for STI EZPath and Hilti devices, and open pathway sizing for J-hooks, cable baskets, and Arlington loops. Select Fill. When developing our cable support OBO can offer reliable solutions for systems, three attributes are at the routing and fastening cables securely core of what we do: efficiency, resil- for each of these installation challeng-ience and safety. es in the industrial environment. IEC 61537 covers cable tray and cable ladder systems for the support and accommodation of cables, while NEC Article 392 governs cable.