How large is the butterfly-shaped optical cable

The typical outer diameter of a butterfly-shaped optical cable is 6.8 mm.Butterfly-shaped optical cables are designed with a flat, wing-like cross-section, where the optical fiber sits in the center and is flanked by two parallel strength members, usually made of Fiber Reinforced Plastic (FRP) or sometimes steel for outdoor self-supporting variants . This geometry provides directional flexibility, allowing the cable to bend easily along its flat plane while resisting sharp kinks edge-on, which protects the fiber core during installation . The 6.8 mm diameter applies to armoured FTTH butterfly-shaped cables, which include additional protective layers such as a PE or LSZH outer sheath, steel tape for moisture resistance, and internal strength members for tensile and compression performance . This compact size ensures efficient conduit entry, minimal space occupation, and easier handling in both indoor and outdoor deployments .Structural Features Affecting DiameterCore fiber unit: Positioned centrally for optimal protection and signal integrity.Strength members: Two parallel FRP rods or a steel wire for tensile support.Sheath layers: LSZH or PE outer sheath, sometimes with steel tape for moisture and UV protection.Bend-resistant fibers: Typically ITU-T G.657 single-mode fibers, allowing tight bend radii without signal loss . The butterfly-shaped design allows for lightweight, flexible, and easy-to-install cables while maintaining durability and performance, making the 6.8 mm diameter suitable for residential, commercial, and pipeline applications . For specific deployments, variations in fiber count, armouring, or sheath type may slightly alter the effective diameter, but 6.8 mm is the standard reference for most armoured FTTH butterfly cables .