Technical guide to firestopping cable tray and slab penetrations in electrical shafts; specifies materials, packing limits, waterstop heights and installation sequence. Where cables pass through shafts, walls, slabs, or enter electrical panels or cabinets, openings shall be tightly sealed with firestopping materials in accordance with. Cable tray installation must comply with specific technical standards to ensure electrical safety, system reliability, and long-term maintainability. Route. In addition, this document contains several references to provisions of the National Electric Code (NEC), which is published by the National Fire Protection Association (NFPA). The content is written to be SEO-friendly and compatible with Yoast SEO for WordPress. However, the cable tray may be centered directly below some.