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Electrical conductivity is a measure of how well a material transports an electric charge.This is an essential property in electrical wiring systems. Copper has the highest electrical conductivity rating of all non-precious metals: the electrical resistivity of copper = 16.78 nΩ•m at 20 °C.
Sometime around 1913, several copper samples from 14 important refiners and wire manufacturers were analyzed by the U.S. Bureau of Standards. The average resistance of the samples was determined to be 0.15292 Ω for copper wires with a mass of 1 gram of uniform cross section and 1 meter in length at 20 °C. In the United States this is usually ...
29 Cu copper; use 2.15 nΩm 15.43 nΩm 16.78 nΩm 17.12 nΩm 17.25 nΩm ... 273 K (0 °C) 293 K (20 °C) 298 K (25 °C) 300 K (27 °C) 500 K (227 °C) References
Copper fittings for soldered plumbing joints A very large copper seal end cap. The major applications of copper are electrical wire (60%), roofing and plumbing (20%), and industrial machinery (15%). Copper is used mostly as a pure metal, but when greater hardness is required, it is put into such alloys as brass and bronze (5% of total use). [28]
The 20 °C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at 0 °C. [53] The extremely low resistivity (high conductivity) of silver is characteristic of metals.
As quoted from various sources in an online version of: David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition.CRC Press. Boca Raton, Florida, 2003; Section 12, Properties of Solids; Thermal and Physical Properties of Pure Metals / Thermal Conductivity of Crystalline Dielectrics / Thermal Conductivity of Metals and Semiconductors as a Function of Temperature
Also some de Vries authorities include John Webb, "Thermal Conductivity of Soil" November 1956, Nature Volume 178, pages 1074–1075, and M.W. Makowski, "Thermal Conductivity of Soil" April 1957, Nature Volume 179, pages 778-779 and more recent notables include Nan Zhang Phd and Zhaoyu Wang PhD "Review of soil thermal conductivity and ...
For comparison purposes reference values are reported at an agreed temperature, usually 298 K (≈ 25 °C or 77 °F), although occasionally 20 °C (68 °F) is used. So-called "compensated" measurements are made at a convenient temperature but the value reported is a calculated value of the expected value of conductivity of the solution, as if ...