Some tapes, wraps, and separators can also perform additional functions. • Aluminized backing can be used for shielding and insulation. • Binder wraps hold components together to make sure tensions stay the same. • Some tapes can increase flex life or rigidity. Others are specifically designed for high or low temperatures, or for use in any temperature. • Wraps and tapes can be designed to protect cable or components from moisture and chemicals. What to ask when selecting tapes, wraps, and separators: • What internal components must be accommodated? • What other functions would be helpful for this application? • How will the cable be connectorized? • Will the choice of material affect the connector housing? SHIELDING FOR STRUCTURAL AND SIGNAL INTEGRITY Shielding protects the cable by increasing structural integrity and signals integrity. With the right materials and configurations, shielding can also add strength, flexibility, and noise suppression. Shielding is accomplished with aluminum foil tape; aluminized polyester tape; foil tape, braiding with tinned copper, stainless steel, bronze, and other materials; or drain wire. A combination of braid shields, which guard against low frequency noise, and foil shields, which guard against high frequency noise, is most effective against interference for maintaining signal integrity. Braiding styles are either
box weave or spiral.
What to ask when choosing shielding: • What type of noise interference will the cable encounter? • What are the flex life demands for the cable system? • What is the plan for connectorizing multiple shields? JACKETING PROVIDES DEFENSE AGAINST HARSH ENVIRONMENTS The outer jacket is a cable’s main protection against environmental stresses and application demands. For medical and food grade applications, polyurethane, thermoplastic rubber, and polyvinyl chloride are used. Options for other applications include fluoropolymers, polyester elastomer, thermoplastic elastomer, and thermoplastic urethane. In some cases, a specialty blend is appropriate to meet specific, unique needs. What to ask when choosing jacket materials: • Will the cable be subjected to extreme temperatures? • Is cut, crush, or abrasion resistance required? • Are there low smoke, zero halogen (LSZH) requirements? • Are there medical or food grade considerations? CONSIDER THE CONNECTOR The connection is often the part of the assembly that is most vulnerable to the elements, so attention to terminating and connectorizing the cable is critical. The connector must have its own protection against the elements and operating conditions that exist in harsh environments: extreme temperatures or temperature fluctuations, chemicals, water, dust, sunlight, radiation, and more.
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