Some wire manufacturers specialize in designing rope lay cables, concentric and miniature bunched strands that offer the ultimate in flexibility. These stranded constructions complement specialty insulated wire products, where flexibility and extended flex-life are primary concerns.
By combining smaller wire gauges into larger conductors, the overall conductor’s geometric resistance to bending and therefore it’s stiffness, is reduced as demonstrated in Fig. 1 comparing the stiffness percentage of several 28 AWG stranding (7/36 is considered to be 100% in this example).
In addition to reducing stiffness, smaller gauge sizes also develop less stress when subjected to bending. As a result conductors with finer stranding will survive a larger number of bending cycles without suffering fatigue in comparison to a conductor manufactured with a coarser single end wire.
In bunching operations a large number of wires are assembled by twisting them together through a rotating arm. Bunched conductors have higher packing density than cabled conductors, at the expense of reduced flexibility and some introduced twist in the individual wires.
For applications that require flexibility at larger conductor sizes, New England Wire offers ultra flexible ropelay cables. These ropelay are constructed of fine wire that is bunched and then cabled concentrically at specific lay lengths to maximize flexibility without impacting performance or aesthetics typically utilizing 44-52 AWG single end wire. Cabled conductors tend to maintain a circular shape better than a bunched conductor, in addition to improving flexibility by reducing strand interaction (or bunch interaction in larger ropelays).