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In electrical applications, copper and its alloys play a very
important role, due to their inherent unique mechanical and physical
properties.
Copper has the highest electrical conductivity of the commercial
metals, except silver. The electrical conductivity of annealed
copper at 20°C (68°F), is the standard to which all other metals
and alloys are compared. It is arbitrarily established at 100%
IACS (International Annealed Copper Standard). Of equal importance
are its strength, formability, ease of joining, resistance to
creep, high thermal conductivity, and resistance to corrosion.
The high electrical conductivity of copper means that a smaller
conductor size is required, compared with other materials, to
carry the power load for a particular service, which is a very
important factor. Less expense is incurred in providing the insulation,
shielding and armouring the cables. The smaller size provides
greater cable flexibility, ease of installation and transportation.
Copper cables are easily joined because copper does not form a
tough non-conducting oxide on its surface. The oxide film that
forms is thin, strongly adherent and electrically conductive.
With all metals, electrical conductivity varies with temperature.
If a metal becomes over-heated from inadvertent electrical overload,
then its conductivity is reduced, which aggravates the temperature
situation. Copper is well known for its excellent performance
under such adverse conditions.
The unique characteristics of copper are the reason for there
being so many different types of copper-conductor cables available,
making them extremely versatile and the chosen product for an
extensive range of applications. Important advantages of copper
installations are high performance, reliability and low maintenance.
Relative Conductivities
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