Cable must be designed to minimize strain on the conductors to maintain power and signal performance. Adding a strength member to the cable construction is frequently the easiest and most effective way to accomplish this objective.

Strength Members

Materials

• Synthetic & natural fibers are the most common, including:
• Kevlar ®
• Polyester,
• Polypropylene,
• Nomex ®, and
• Cotton

These fibers offer effective strength to weight ratios; they are light and flexible. Other materials used for strength and support include galvanized carbon steel, carbon fibers, glass fibers, and glass reinforced plastics.

Orientation

The strength members are commonly placed as a center member in a round cable and as an integral (embedded in the plastic) support member in flat constructions. Strength members can be placed throughout a round cable including outside the cable core assembly in a braid, helical or longitudinal application. A jacket is typically applied over the outside strength members.

Design Considerations

In addition to strength, flexibility, torsional balance (tendency of the cable to untwist or turn under load), cable weight, additional payload, dynamic loads, flexibility, flame resistance, internal and external abrasion resistance, and temperature performance need to be considered depending upon the application.