“You cannot bring the OSP (non-flame rated) cable more than 50' into the building. For metallic cables I must use RMC, IMC only. If this. What if you have unlisted cables entering a building? First, understand what the “point of entrance” is — the point within a building at which the optical fiber cable emerges from one of these [770. Each type is designed with specific features to ensure optimal performance under varying conditions. Indoor fiber optic cables are commonly used in buildings, offices. Part II of Article 770 provides the requirements for cables outside and entering buildings. Conductive. “To extend into a building beyond 50 ft, the conduit entering the wall or concrete floor slab needs to be extended with IMC or RMC conduit. Extending the. e National Electrical Code (NFPA 70).
