What is the outer diameter in mm of a 48-core multimode optical cable

The outer diameter of a 48-core multimode optical cable typically ranges from 12 mm to 18 mm, depending on the design and protective layers.

Cable Structure and Diameter Considerations

A 48-core multimode fiber optic cable consists of multiple layers that contribute to its overall diameter: Fiber cores: Each multimode fiber has a core diameter of 50 µm or 62. 5 µm, with a standard cladding diameter of 125 µm and a protective coating of 250 µm or 900 µm for tight-buffered fibers. Buffer and tube layers: Fibers are grouped into buffer tubes (loose-tube or tight-buffered), which typically range from 2 mm to 3 mm in diameter for outdoor or rugged designs.

Outer jacket: The final protective layer, often made of polyethylene or PVC, adds 1. 6 mm to 3 mm depending on environmental protection requirements.

Typical Outer Diameter Ranges

Indoor, tight-buffered designs: Approximately 12–14 mm outer diameter. Outdoor, loose-tube or armored designs: Approximately 14–18 mm outer diameter, with armored versions slightly larger due to steel or Kevlar reinforcement.

Example Specifications

Belden and Mtech 48-core multimode cables report outer diameters in the 12–18 mm range, depending on whether the cable is loose-tube, gel-free, or armored. Corning ALTOS® 48-fiber OM3 multimode loose-tube cables typically fall within 14–16 mm outer diameter for outdoor duct installations.

Summary

The outer diameter of a 48-core multimode optical cable is not fixed and depends on the cable construction, environmental protection, and fiber grouping method. For most standard indoor and outdoor installations, you can expect a diameter between 12 mm and 18 mm, with armored or heavily reinforced cables at the higher end of this range. This information is essential for conduit sizing, cable trays, and installation planning.