Glossary

Termination efficiency is the percentage of a rope, cable, or sling’s rated breaking strength that is retained at its end connection (termination) compared to the strength of the un-terminated line. It reflects how much strength is “lost” because the termination introduces stress concentrations, bending, friction, or damage to the fibers/wires, making the assembly break at a lower load than the raw rope/cable would in a straight pull.

It’s commonly expressed as:

Termination efficiency (%) = (Breaking strength of the terminated assembly ÷ Breaking strength of the rope/cable) × 100

In rigging and industrial hardware, termination efficiency depends heavily on the termination method and workmanship. Swaged sockets, poured/resin sockets, and properly fabricated mechanical splices can achieve very high efficiency, while wire rope clips, knots, sharp-radius bends, and poorly executed eye splices reduce efficiency significantly. It’s also affected by the rope construction (6×19 vs 6×37, IWRC vs fiber core), sling type, thimble use, the D/d ratio (bend diameter to rope diameter), corrosion, wear, and whether the termination slips or crushes the rope.

Termination efficiency matters because it directly influences the Minimum Breaking Load/Strength of the assembly and therefore the Working Load Limit and safety of the rigging system. In many failures, the rope itself isn’t the weak link—the termination is—so specifications often require approved termination types and installation practices to achieve the intended efficiency.