The outer diameter of a 48-core optical fiber cable typically ranges from 9 mm to 14 mm, depending on construction and armoring.

Typical Cable Types and Diameters

• Loose Tube Gel-Free Cables: For example, Corning ALTOS® 48-fiber loose tube cables are designed for duct and aerial installations. These cables are flexible, water-blocked, and have a medium-density polyethylene (MDPE) jacket. Their outer diameter is generally around 9–12 mm for 48-core configurations .
• Armoured Loose Tube Cables: Armoured cables, such as Enbeam OS2 48-core CST (corrugated steel tape) cables, provide mechanical protection and rodent resistance. The armoring increases the outer diameter, typically to 12–14 mm .
• Indoor-Outdoor Armoured Cables: Some hybrid indoor-outdoor armoured cables, like those from Panduit, may have slightly larger diameters due to additional fire-retardant and water-blocking layers, often in the 12–13 mm range .

Factors Affecting Outer Diameter

1. Fiber Count: Higher fiber counts increase the number of buffer tubes, slightly enlarging the cable diameter.
2. Armoring: Steel tape or aluminum armoring adds 2–3 mm to the base diameter.
3. Jacket Material: Polyethylene (PE), low-smoke zero-halogen (LSZH), or flame-retardant jackets can vary in thickness.
4. Cable Design: Loose tube vs. tight-buffered designs influence the compactness and diameter.

Practical Considerations

• When planning conduit installation, allow 10–20% extra space beyond the cable diameter for ease of pulling and thermal expansion.
• Verify the exact diameter with the manufacturer's datasheet for the specific cable model, as variations exist between brands and construction types . In summary, for a 48-core optical fiber cable, expect an outer diameter of approximately 9–14 mm, with loose tube gel-free cables on the smaller end and armoured cables on the larger end. Always confirm with the specific product datasheet for precise conduit sizing.