Attempts to replace copper with aluminium in building wire were curtailed in most countries when it was found that aluminium connections gradually loosened due to their inherent slow creep, combined with the high resistivity and heat generation of aluminium oxidation at joints. Resistance formula is: R = ρL/A Where: ρ: Resistivity constant of the material, in Ω.m L: Length of the wire, in meter A: Cross sectional area of the wire, in m^2 R: Resistance, in ohms (Ω) We can rearrange it to get a formula for resistivity: b) A wire made of a copper alloy is 5 m in length and has a cross-sectional area 1 mm2. [1][2] The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor. These closures can be used in a variety of applications, including branch splicing. The smaller the resistivity, the better the material is at conducting electricity. Resistivity ρ, unlike resistance, is an intrinsic property of a material.It means that it doesn't matter whether the wire is thick or thin, long or short. However they are the easiest to tap into. Because of these factors, copper is widely used for electrical purposes such as household electrical wires, electrical machinery and generators and is able to withstand the elements to be used in outdoor power lines. In-line closures can also be used in a butt configuration by restricting cable access to one end of the closure. In electrical systems, high thermal conductivity is important for dissipating waste heat, particularly at terminations and connections. 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/DeviceGray endobj 40 0 obj << /Filter /FlateDecode /Length 41 0 R >> stream It resists corrosion and is a good conductor of heat and has a high conductivity when it comes to electricity. Next suppose we connect the two identical conductors together in parallel combination as shown. Thus the higher the resistivity value of ρ the more resistance and vice versa. Hopefully it'll be a breeze. But as well as doubling the length, we have also doubled the total resistance of the conductor, giving 2R as: 1R + 1R = 2R. This copper is at least 99.90% pure and has an electrical conductivity of at least 101% IACS. Properties of copper Electrical conductivity. The combination of all of these factors makes it easy for electricians to install copper wire.[17][21]. [13], Thermal conductivity is the ability of a material to conduct heat. Conductivity ranges from zero (for a perfect insulator) to infinity (for a perfect conductor). • Carry out calculations involving resistivity & resistance. What if my area is in mm and the length in m how will i work it out? Solid wire consists of one strand of copper metal wire, bare or surrounded by an insulator.