Tinsel wire

Tinsel wire is a form of electrical wire used when maximum mechanical flexibility is desired. It is commonly found in cords used for telephones, especially the handset cords. Because of its extreme flexibility, it is very resistant to failing as a result of metal fatigue. In this way it is different than ordinary stranded wire or, especially, solid wire.

Tinsel wire is made by wrapping several strands of thin copper foil around a textile core. Because the foil is very thin, its is extremely flexible. In addition, the extreme thinness of the foil means that the maximum bend radius imposed on the foil is many times the thickness of the foil, leading to a low probability of metal fatigue. Meanwhile, the fabric core provides high tensile strength.

Separated from the core, the individual foils are relatively fragile, and the core can be damaged by high heat. Together, these two factors make it difficult or impractical to terminate tinsel wire by soldering. Instead, crimped connections are commonly used. Usually, the connector has a series of barbs that pierce the insulation that covers the tinsel wire, allowing the connection to be made without any need to strip the insulation for the conductor.