Conductor Constructions
For electronic equipment, copper is by far the most used conductor material. It has excellent electrical conductivity, high thermal conductivity, great resistance to corrosion and superior solderability. Copper conductors are available with a thin, electroplated tin coating (tinned copper), or no coating (bare copper). Tinned copper offers easier solderability while bare copper offers lower cost.
Commonly used stranded conductors in electronics have 7,10,16,19,26,41,65,105 or even a greater number of strands. Kemcor uses both solid and stranded constructions, as specified by customer requirement or agency mandate. Stranded conductors offer certain advantages over solids.
Flexibility: Much greater than an equal sized solid conductor. Makes processing easier.
Flex Life: Substantially better than solid wire. Can withstand far more vibration and bending before breaking.
Surface Damage: Scratching or nicking while stripping is far less serious than with solid wires.
Stranding Types
Bunch stranding: Composed of any number of strands twisted together in the same direction without regard to arrangement of the individual strands. It is used in many commercial applications, offers greater flexibility and lowest cost.
The next construction types have helically laid strands around a central strand. True concentric and equilay have the greatest mechanical strength and crush resistance; unilay, the lightest weight and smallest diameter. These constructions can be more uniformly centered in the insulation than bunched wire.
True Concentric: A central strand surrounded by one or more layers with lay direction reversed and lay length increased for each layer.
Unidirectional Concentric: Same as above except that lay direction is the same in all layers.
Unilay: Same as true concentric except that lay length is the same in all layers.
Equilay: Both lay length and lay direction are the same in all layers.
Rope Stranding: Composed of concentrically cabled groups of any of the above types. Most flexible of all, this construction is generally used for conductors 8 AWG and larger.
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