Dimensions of Double-Butterfly Optical Cable

Double-Butterfly Optical Cables feature a flat, wing-shaped profile with central optical fibers flanked by parallel strength members, typically reinforced with FRP or steel, and enclosed in a LSZH or PVC sheath.Cable StructureA double-butterfly optical cable has a flat, winged cross-section where the optical fiber unit is positioned in the center. On either side of the fiber, two parallel strength members are placed, usually made of Fiber Reinforced Plastic (FRP) for indoor cables or FRP combined with a steel wire messenger for self-supporting outdoor variants . This design provides directional flexibility, allowing bending along the flat plane with minimal stress while resisting sharp kinks when bent edge-on .Typical DimensionsWidth and Thickness: While exact dimensions vary by manufacturer and fiber count, typical indoor butterfly cables are approximately 3–5 mm thick and 6–8 mm wide, depending on the number of fibers (1–12 cores) and sheath type .Strength Members: The FRP rods are usually 1–2 mm in diameter, and if a steel messenger is included for outdoor aerial deployment, it adds an additional 2–3 mm to the overall thickness .Sheath: The outer sheath is commonly LSZH (Low Smoke Zero Halogen) for indoor use or PVC/LSZH for outdoor aerial cables, contributing 0.5–1 mm to the total thickness .Fiber Placement and Bend RadiusThe optical fiber sits centrally within the cable, often in a loose tube or tight-buffered configuration.Bend-insensitive fibers (ITU-T G.657 standard) are used to tolerate minimum bend radii of 10 mm (A1 type), with A2 or B3 variants for tighter conduit bends .SummaryThe double-butterfly design ensures mechanical protection, directional flexibility, and ease of installation. Its flat profile allows routing along walls, ceilings, or through conduits, while the parallel strength members provide crush resistance and tensile strength. Typical dimensions for a 2–12 fiber indoor cable are 6–8 mm wide and 3–5 mm thick, with strength members of 1–2 mm and optional steel messenger for outdoor use .