Cable Installation Practices (Pulling, Routing, and Support)
Tension and bend radius
Two numbers govern every pull: maximum tensile load and minimum bend radius. The manufacturer's rating always wins. Common indoor fiber limits are in the 25–50 lb (111–222 N) range, while OSP cable can be rated to several hundred pounds. During a pull, keep the bend radius at roughly 20× the cable diameter; once installed and tied, about 10× (some specs use 15×) is the usual minimum. A kink or a tight tie-down creates macrobending loss that may show up only at 1550 nm or only after temperature cycling.
Pulling technique
Use a swivel and a breakaway link set below the cable's rating, pull smoothly by hand where possible, and use a compatible lubricant only where the manufacturer and the conduit/duct allow it. Never pull fiber by the strength members of a breakout without verifying the cable design; never drag cable over sharp tray edges, and use corner rollers/sheaves at direction changes. Exceeding the bend radius or the tension is the most common cause of latent damage.
Routing and support
Horizontal cable is generally supported every 1.2–1.5 m (4–5 ft); vertical riser cable needs more frequent support per TIA-569 and the manufacturer - every floor or at short intervals, not just at the top. Use J-hooks or trapeze supports sized for the bundle (do not overfill), keep conduit fill at or under the code/standard limit (often 40%), and maintain separation from power and EMI sources.
Firestopping and pathways
Every penetration of a fire-rated wall or floor must be sealed with a listed firestop system (ASTM E814/UL 1479). Leave slack (a service loop) at each end and at every splice point.
Rule of thumb
If a pull feels like it needs more force than two people can apply comfortably by hand on indoor cable, stop and re-evaluate the pathway rather than adding tension.