SD is an abbreviation for soft drawn, describing annealed copper that has been softened for flexibility and workability, in contrast to hard drawn wire.
SD stands for soft drawn, a term describing copper wire that has been annealed, or heat-treated, to soften it after drawing. Drawing copper through dies work-hardens it, and annealing relieves that hardness, leaving the wire soft, flexible, and easy to bend and work. Soft drawn copper is the opposite of hard drawn copper, which retains its strength and stiffness.
Because soft drawn copper is flexible and pliable, it is used where workability and bendability matter more than mechanical strength, such as in many insulated building and equipment wires. The annealing also gives soft drawn copper its full electrical conductivity.
In commercial and industrial wire, the temper of copper, including soft drawn, is matched to the application's needs for flexibility and strength. Recognizing the SD designation is part of understanding a conductor's mechanical character.
Because soft drawn copper is flexible and pliable, it is used where workability and bendability matter more than mechanical strength, such as in many insulated building and equipment wires, and the annealing that softens it also restores the metal's full electrical conductivity.
Recognizing the SD designation is part of understanding a conductor's mechanical character, since soft drawn copper provides flexibility and full conductivity where workability matters.
At Windy City Wire, an understanding of conductor characteristics, including copper temper like soft drawn, supports the selection of wire suited to an application. Recognizing how soft drawn copper provides flexibility and conductivity helps customers match conductors to their commercial and industrial needs.
SD (soft drawn, annealed)