Fiber Optic Cable Armor Connection Method

Armored fiber optic cables require careful armor removal, proper pulling techniques, and secure attachment to connectors or pulling elements to ensure reliable performance and mechanical protection.

Understanding Armored Fiber Cables

Armored fiber optic cables feature a protective layer—typically steel, aluminum, or Kevlar—between the optical fibers and the outer jacket, designed to resist crushing, bending, moisture, rodents, and mechanical stress. There are two main types: interlocked armor, which is flexible and often used in conduits, and metallic or corrugated armor, which provides higher crush resistance. The inner fiber is usually not bonded to the armor, so proper connection and pulling methods are essential to prevent separation.

Armor Removal and Preparation

Bend and Separate: Bend the cable about 10 inches from the end and apply pressure to loosen the armor coils. Pliers or specialized cutting tools may be used if manual force is insufficient. Twist and Release: Grip the cable on both sides of the cut and twist the armor counter-clockwise until it separates from the inner fiber.

Trim Exposed Armor: Use side cutters to remove sharp edges and any residual metal or plastic strips for a clean finish. Remove Outer Jacket: If present, carefully strip the outer jacket without damaging the inner fibers.

Connection and Pulling Methods

Kellems Grip or Cable Pulling Tool: For interlocked armored cables, attach a pulling grip to both the inner cable and the armor to distribute tensile forces evenly. This prevents the armor from separating during installation. Tensile Load Consideration: Always check the cable's rated pull strength.

Exceeding the armor's pull limit can cause separation or fiber damage. Industrial armored cables may support higher tensile loads, but dynamic pulling should remain within manufacturer specifications. Bend Radius Compliance: Maintain the minimum bend radius during routing to avoid fiber breakage.

For single-mode armored cables, typical bend radii are 10D (dynamic) and 5D (static), while multimode cables may require 20D/10D. Grounding: Metal-armored cables may require grounding to prevent electrical hazards, especially in outdoor or industrial installations. Ensure compliance with local electrical codes.

Final Steps

After armor removal and proper pulling, proceed with standard fiber termination procedures: cleaning, cleaving, and connector attachment. Test the fiber for continuity, insertion loss, and return loss to ensure signal integrity. Proper handling and connection of armored fiber cables ensure durability, reliability, and long-term performance in harsh environments.

By following these steps, armored fiber optic cables can be safely installed and connected, maintaining both mechanical protection and optical performance.