What is a Cable Strength Member?
A strength member is the supporting component that preserves the cable integrity. Strength members add both function and protection to your connectivity solution. There are several options including steel, aramid fiber, or a stiff fiberglass rod that runs the length of the center of the cable. The strength member helps the cable withstand different types of movement including:
Why do you need a Cable Strength Member?
Strength members offer reinforcement to cables that perform in tough or rugged environments. The strength member core makes sure that there isn’t pull on the connector. They offer support, strength, and added longevity to the cable.
How to choose a Strength Member?
Ask these questions when deciding what material and type of strength member is needed:
- What is the pull strength requirement?
- Does this cable need to be flexible?
- Does the strength member need to be terminated to the connector?
Strength Member Material Choices
Aramid fiber, such as Kevlar® is a strong material ideal for extreme pulling strength. Aramid fiber can be stranded in a variety of configurations to achieve differing levels of strength. A bundle of four strands provides 450-600 Newtons of pull strength. While it is not rigid, it does offer high compressive strength without adding significant weight. If aramid fiber is used in a cable system, special attention must be given to the cable’s termination, as incorrect termination can lead to weak points in the fiber.
Steel strength members are used in applications where pulling strength and compressive strength are critical. There are different types of steel strength members that may be used depending on weight requirements and durability. Stainless steel strength members provide excellent strength at just 3/16th of an inch. Galvanized steel provides pull strength of about 500 Newtons without breaking, along with superior compressive strength.
Fiberglass rods are extremely rigid and good matches for pulling or pushing applications. The fiberglass has great compressive properties and is very strong. It is important to consider the environment since fiberglass cannot handle extreme heat or cold. It cracks below -20C and above 80C.
A custom cable designed for a demanding end application without a strength member is like the Wild West without cowboy hats, it just isn’t right.